Safe Drinking Water Regulations Tool

Antimony

• MCL/MCLG (mg/L unless noted): 0.006 / 0.006
• Health Effects: Increase in blood cholesterol; decrease in blood sugar
• Monitoring Requirements/Comments: For IOCs: Once a year for surface water; once every 3 years for ground water (not including Asbestos, Lead and Copper, Nitrate, Nitrite and Radionuclides). Minimize monitoring costs by using historical data, waivers, susceptibility waivers, and/or making composite samples.

Asbestos (fiber length > 10 micrometers)

• MCL/MCLG (mg/L unless noted): 7 MFL/7MFL
• Health Effects: Increased risk of developing benign intestinal polyps
• Monitoring Requirements/Comments: Once every nine years.

Barium

• MCL/MCLG (mg/L unless noted): 2/2
• Health Effects: Increase in blood pressure
• Monitoring Requirements/Comments: For IOCs: Once a year for surface water; once every 3 years for ground water (not including Asbestos, Lead and Copper, Nitrate, Nitrite and Radionuclides). Minimize monitoring costs by using historical data, waivers, susceptibility waivers, and/or making composite samples.

Beryllium

• MCL/MCLG (mg/L unless noted): 0.004/0.004
• Health Effects: Intestinal lesions
• Monitoring Requirements/Comments: For IOCs: Once a year for surface water; once every 3 years for ground water (not including Asbestos, Lead and Copper, Nitrate, Nitrite and Radionuclides). Minimize monitoring costs by using historical data, waivers, susceptibility waivers, and/or making composite samples.

Cadmium

• MCL/MCLG (mg/L unless noted): 0.005/0.005
• Health Effects: Kidney damage
• Monitoring Requirements/Comments: For IOCs: Once a year for surface water; once every 3 years for ground water (not including Asbestos, Lead and Copper, Nitrate, Nitrite and Radionuclides). Minimize monitoring costs by using historical data, waivers, susceptibility waivers, and/or making composite samples.

Chromium (total)

• MCL/MCLG (mg/L unless noted): 0.1/0.1
• Health Effects: Allergic dermatitis
• Monitoring Requirements/Comments: For IOCs: Once a year for surface water; once every 3 years for ground water (not including Asbestos, Lead and Copper, Nitrate, Nitrite and Radionuclides). Minimize monitoring costs by using historical data, waivers, susceptibility waivers, and/or making composite samples.

Copper (revisions & clarifications)

• MCL/MCLG (mg/L unless noted): TT (AL = 1.3) / 1.3
• Health Effects: Gastrointestinal/liver/kidney problems
• Monitoring Requirements/Comments: Copper: Same as Lead.

Cyanide (as free cyanide)

• MCL/MCLG (mg/L unless noted): 0.2/0.2
• Health Effects: Thyroid/neurological effects
• Monitoring Requirements/Comments: For IOCs: Once a year for surface water; once every 3 years for ground water (not including Asbestos, Lead and Copper, Nitrate, Nitrite and Radionuclides). Minimize monitoring costs by using historical data, waivers, susceptibility waivers, and/or making composite samples.

Fluoride

• MCL/MCLG (mg/L unless noted): 4.0/4.0
• Health Effects: Bone disease
• Monitoring Requirements/Comments: For IOCs: Once a year for surface water; once every 3 years for ground water (not including Asbestos, Lead and Copper, Nitrate, Nitrite and Radionuclides). Minimize monitoring costs by using historical data, waivers, susceptibility waivers, and/or making composite samples.

Lead (revisions & clarifications)

• MCL/MCLG (mg/L unless noted): TT (AL = 0.015) / 0
• Health Effects: Kidney problems; high blood pressure; infants and children - delays in physical or mental development
• Monitoring Requirements/Comments: Residential sample taken at the kitchen or bathroom sink tap. ALs must be met in 90% of the samples. Follow-up monitoring every 6 months after corrosion controls initiated or optimized. Reduced monitoring for systems consistently meeting AL. An AL exceedance is not a violation but can trigger other requirements that include water quality parameter monitoring, corrosion control treatment, source water monitoring/treatment, public education, and lead service line replacement.

Mercury (inorganic)

• MCL/MCLG (mg/L unless noted): 0.002/0.002
• Health Effects: Kidney damage
• Monitoring Requirements/Comments: For IOCs: Once a year for surface water; once every 3 years for ground water (not including Asbestos, Lead and Copper, Nitrate, Nitrite and Radionuclides). Minimize monitoring costs by using historical data, waivers, susceptibility waivers, and/or making composite samples.

Nitrate (as N)

• MCL/MCLG (mg/L unless noted): 10/10
• Health Effects: Methemoglobinemia (blue baby syndrome)/diuresis
• Monitoring Requirements/Comments: Ground water annually; surface water quarterly initially, then annually.

Nitrite (as N)

• MCL/MCLG (mg/L unless noted): 1/1
• Health Effects: Methemoglobinemia (blue baby syndrome)/diuresis
• Monitoring Requirements/Comments: One sample during first 3-year compliance period. Repeat frequency determined by state.

Selenium

• MCL/MCLG (mg/L unless noted): 0.05/0.05
• Health Effects: Hair or fingernail loss; numbness of fingers or toes; circulatory problems
• Monitoring Requirements/Comments: For IOCs: Once a year for surface water; once every 3 years for ground water (not including Asbestos, Lead and Copper, Nitrate, Nitrite and Radionuclides). Minimize monitoring costs by using historical data, waivers, susceptibility waivers, and/or making composite samples.

Thallium

• MCL/MCLG (mg/L unless noted): 0.002/0.0005
• Health Effects: Hair loss; changes in blood; kidney/liver/intestinal problems
• Monitoring Requirements/Comments: For IOCs: Once a year for surface water; once every 3 years for ground water (not including Asbestos, Lead and Copper, Nitrate, Nitrite and Radionuclides). Minimize monitoring costs by using historical data, waivers, susceptibility waivers, and/or making composite samples.

Arsenic

• MCL/MCLG (mg/L unless noted): 0.010/0
• Health Effects: Cancer risk; cardiovascular and dermal problems
• Monitoring Requirements/Comments: Same as IOCs. Applies to CWS and NTNCWS.

Combined Radium-226 and Radium-228 (Radionuclides)

• MCL/MCLG (mg/L unless noted): 5 pCi/L / 0
• Health Effects: Cancer risk
• Monitoring Requirements/Comments: Sample point is the distribution system entry point that is representative of all sources being used. Four consecutive quarterly samples must be taken at all sample points. Rule applies to Community Water Systems only.

Radionuclides: Combined Radium-226 and Radium-228

• MCL/MCLG (mg/L unless noted): 5 pCi/L / 0
• Health Effects: Cancer risk
• Monitoring Requirements/Comments: Sample point is the distribution system entry point that is representative of all sources being used. Four consecutive quarterly samples must be taken at all sample points. Rule applies to Community Water Systems only.

Gross Alpha - excluding radon and uranium (Radionuclides)

• MCL/MCLG (mg/L unless noted): 15 pCi/L / 0
• Health Effects: Cancer risk
• Monitoring Requirements/Comments: Sample point is the distribution system entry point that is representative of all sources being used. Four consecutive quarterly samples must be taken at all sample points. Rule applies to Community Water Systems only.

Radionuclides: Gross Alpha - excluding radon and uranium

• MCL/MCLG (mg/L unless noted): 15 pCi/L / 0
• Health Effects: Cancer risk
• Monitoring Requirements/Comments: Sample point is the distribution system entry point that is representative of all sources being used. Four consecutive quarterly samples must be taken at all sample points. Rule applies to Community Water Systems only.

Beta Particles and Photon Emitters (Radionuclides)

• MCL/MCLG (mg/L unless noted): 4 mrem/year / 0
• Health Effects: Cancer risk
• Monitoring Requirements/Comments: Primacy agency must designate vulnerable systems. Once deemed vulnerable, quarterly samples required for beta emitters and annual samples for Tritium and Strontium-90 at entry to distribution system. Compliance is based on the running annual average of four quarterly samples taken at each sample point.

Radionuclides: Beta Particles and Photon Emitters

• MCL/MCLG (mg/L unless noted): 4 mrem/year / 0
• Health Effects: Cancer risk
• Monitoring Requirements/Comments: Primacy agency must designate vulnerable systems. Once deemed vulnerable, quarterly samples required for beta emitters and annual samples for Tritium and Strontium-90 at entry to distribution system. Compliance is based on the running annual average of four quarterly samples taken at each sample point.

Uranium (Radionuclides)

• MCL/MCLG (mg/L unless noted): 0.030/0
• Health Effects: Kidney problems/cancer risk
• Monitoring Requirements/Comments: Same as Combined Radium and Gross Alpha.

Radionuclides: Uranium

• MCL/MCLG (mg/L unless noted): 0.030/0
• Health Effects: Kidney problems/cancer risk
• Monitoring Requirements/Comments: Same as Combined Radium and Gross Alpha.

2,3,7,8-TCDD (Dioxin)

• MCL/MCLG (mg/L unless noted): 0.00000003/0
• Health Effects: Cancer risk; reproductive system problems
• Monitoring Requirements/Comments: For SOCs: Four consecutive quarterly samples during first compliance period. Compliance is based on annual average of quarterly samples. If no detections are found during initial round, two quarterly samples are required each year for systems serving > 3,300; one sample is required every 3 years for smaller systems. With the completion of source water assessments, primacy agencies are allowed to develop alternative monitoring requirements. Contact your local primacy agency for further information. Applies to CWS and NTNCWS.

2,4,5-TP (Silvex)

• MCL/MCLG (mg/L unless noted): 0.05/0.05
• Health Effects: Liver problems
• Monitoring Requirements/Comments: For SOCs: Four consecutive quarterly samples during first compliance period. Compliance is based on annual average of quarterly samples. If no detections are found during initial round, two quarterly samples are required each year for systems serving > 3,300; one sample is required every 3 years for smaller systems. With the completion of source water assessments, primacy agencies are allowed to develop alternative monitoring requirements. Contact your local primacy agency for further information. Applies to CWS and NTNCWS.

2,4-D

• MCL/MCLG (mg/L unless noted): 0.07/0.07
• Health Effects: Adrenal gland/liver/kidney problems
• Monitoring Requirements/Comments: For SOCs: Four consecutive quarterly samples during first compliance period. Compliance is based on annual average of quarterly samples. If no detections are found during initial round, two quarterly samples are required each year for systems serving > 3,300; one sample is required every 3 years for smaller systems. With the completion of source water assessments, primacy agencies are allowed to develop alternative monitoring requirements. Contact your local primacy agency for further information. Applies to CWS and NTNCWS.

Acrylamide

• MCL/MCLG (mg/L unless noted): TT/0
• Health Effects: Cancer risk; nervous system/blood problems
• Monitoring Requirements/Comments: For SOCs: Four consecutive quarterly samples during first compliance period. Compliance is based on annual average of quarterly samples. If no detections are found during initial round, two quarterly samples are required each year for systems serving > 3,300; one sample is required every 3 years for smaller systems. With the completion of source water assessments, primacy agencies are allowed to develop alternative monitoring requirements. Contact your local primacy agency for further information. Applies to CWS and NTNCWS.

Alachlor

• MCL/MCLG (mg/L unless noted): 0.002/0
• Health Effects: Cancer risk; eye/liver/kidney/spleen problems
• Monitoring Requirements/Comments: For SOCs: Four consecutive quarterly samples during first compliance period. Compliance is based on annual average of quarterly samples. If no detections are found during initial round, two quarterly samples are required each year for systems serving > 3,300; one sample is required every 3 years for smaller systems. With the completion of source water assessments, primacy agencies are allowed to develop alternative monitoring requirements. Contact your local primacy agency for further information. Applies to CWS and NTNCWS.

Atrazine

• MCL/MCLG (mg/L unless noted): 0.003/0.003
• Health Effects: Cardio problems/reproductive system problems
• Monitoring Requirements/Comments: For SOCs: Four consecutive quarterly samples during first compliance period. Compliance is based on annual average of quarterly samples. If no detections are found during initial round, two quarterly samples are required each year for systems serving > 3,300; one sample is required every 3 years for smaller systems. With the completion of source water assessments, primacy agencies are allowed to develop alternative monitoring requirements. Contact your local primacy agency for further information. Applies to CWS and NTNCWS.

Carbofuran

• MCL/MCLG (mg/L unless noted): 0.04/0.04
• Health Effects: Blood/nervous/reproductive system problems
• Monitoring Requirements/Comments: For SOCs: Four consecutive quarterly samples during first compliance period. Compliance is based on annual average of quarterly samples. If no detections are found during initial round, two quarterly samples are required each year for systems serving > 3,300; one sample is required every 3 years for smaller systems. With the completion of source water assessments, primacy agencies are allowed to develop alternative monitoring requirements. Contact your local primacy agency for further information. Applies to CWS and NTNCWS.

Chlordane

• MCL/MCLG (mg/L unless noted): 0.002/0
• Health Effects: Cancer risk; liver/nervous system problems
• Monitoring Requirements/Comments: For SOCs: Four consecutive quarterly samples during first compliance period. Compliance is based on annual average of quarterly samples. If no detections are found during initial round, two quarterly samples are required each year for systems serving > 3,300; one sample is required every 3 years for smaller systems. With the completion of source water assessments, primacy agencies are allowed to develop alternative monitoring requirements. Contact your local primacy agency for further information. Applies to CWS and NTNCWS.

Dalapon

• MCL/MCLG (mg/L unless noted): 0.2/0.2
• Health Effects: Kidney problems
• Monitoring Requirements/Comments: For SOCs: Four consecutive quarterly samples during first compliance period. Compliance is based on annual average of quarterly samples. If no detections are found during initial round, two quarterly samples are required each year for systems serving > 3,300; one sample is required every 3 years for smaller systems. With the completion of source water assessments, primacy agencies are allowed to develop alternative monitoring requirements. Contact your local primacy agency for further information. Applies to CWS and NTNCWS.

Di(2-ethylhexyl) adipate

• MCL/MCLG (mg/L unless noted): 0.4/0.4
• Health Effects: Liver/weight loss/reproductive system problems
• Monitoring Requirements/Comments: For SOCs: Four consecutive quarterly samples during first compliance period. Compliance is based on annual average of quarterly samples. If no detections are found during initial round, two quarterly samples are required each year for systems serving > 3,300; one sample is required every 3 years for smaller systems. With the completion of source water assessments, primacy agencies are allowed to develop alternative monitoring requirements. Contact your local primacy agency for further information. Applies to CWS and NTNCWS.

1,2- Dibromo-3-chloropropane (DBCP)

• MCL/MCLG (mg/L unless noted): 0.0002/0
• Health Effects: Cancer risk; reproductive system problems
• Monitoring Requirements/Comments: For SOCs: Four consecutive quarterly samples during first compliance period. Compliance is based on annual average of quarterly samples. If no detections are found during initial round, two quarterly samples are required each year for systems serving > 3,300; one sample is required every 3 years for smaller systems. With the completion of source water assessments, primacy agencies are allowed to develop alternative monitoring requirements. Contact your local primacy agency for further information. Applies to CWS and NTNCWS.

Di(2-ethylhexyl) phthalate (DEHP)

• MCL/MCLG (mg/L unless noted): 0.006/0
• Health Effects: Cancer risk; liver/reproductive system problems
• Monitoring Requirements/Comments: For SOCs: Four consecutive quarterly samples during first compliance period. Compliance is based on annual average of quarterly samples. If no detections are found during initial round, two quarterly samples are required each year for systems serving > 3,300; one sample is required every 3 years for smaller systems. With the completion of source water assessments, primacy agencies are allowed to develop alternative monitoring requirements. Contact your local primacy agency for further information. Applies to CWS and NTNCWS.

Dinoseb

• MCL/MCLG (mg/L unless noted): 0.007/0.007
• Health Effects: Reproductive system problems
• Monitoring Requirements/Comments: For SOCs: Four consecutive quarterly samples during first compliance period. Compliance is based on annual average of quarterly samples. If no detections are found during initial round, two quarterly samples are required each year for systems serving > 3,300; one sample is required every 3 years for smaller systems. With the completion of source water assessments, primacy agencies are allowed to develop alternative monitoring requirements. Contact your local primacy agency for further information. Applies to CWS and NTNCWS.

Diquat

• MCL/MCLG (mg/L unless noted): 0.02/0.02
• Health Effects: Ocular problems
• Monitoring Requirements/Comments: For SOCs: Four consecutive quarterly samples during first compliance period. Compliance is based on annual average of quarterly samples. If no detections are found during initial round, two quarterly samples are required each year for systems serving > 3,300; one sample is required every 3 years for smaller systems. With the completion of source water assessments, primacy agencies are allowed to develop alternative monitoring requirements. Contact your local primacy agency for further information. Applies to CWS and NTNCWS.

Endothall

• MCL/MCLG (mg/L unless noted): 0.1/0.1
• Health Effects: Stomach/intestinal problems
• Monitoring Requirements/Comments: For SOCs: Four consecutive quarterly samples during first compliance period. Compliance is based on annual average of quarterly samples. If no detections are found during initial round, two quarterly samples are required each year for systems serving > 3,300; one sample is required every 3 years for smaller systems. With the completion of source water assessments, primacy agencies are allowed to develop alternative monitoring requirements. Contact your local primacy agency for further information. Applies to CWS and NTNCWS.

Endrin

• MCL/MCLG (mg/L unless noted): 0.002/0.002
• Health Effects: Liver problems
• Monitoring Requirements/Comments: For SOCs: Four consecutive quarterly samples during first compliance period. Compliance is based on annual average of quarterly samples. If no detections are found during initial round, two quarterly samples are required each year for systems serving > 3,300; one sample is required every 3 years for smaller systems. With the completion of source water assessments, primacy agencies are allowed to develop alternative monitoring requirements. Contact your local primacy agency for further information. Applies to CWS and NTNCWS.

Epichlorohydrin

• MCL/MCLG (mg/L unless noted): TT/0
• Health Effects: Cancer risk; stomach problems
• Monitoring Requirements/Comments: For SOCs: Four consecutive quarterly samples during first compliance period. Compliance is based on annual average of quarterly samples. If no detections are found during initial round, two quarterly samples are required each year for systems serving > 3,300; one sample is required every 3 years for smaller systems. With the completion of source water assessments, primacy agencies are allowed to develop alternative monitoring requirements. Contact your local primacy agency for further information. Applies to CWS and NTNCWS.

Ethylene Dibromide (EDB)

• MCL/MCLG (mg/L unless noted): 0.00005/0
• Health Effects: Cancer risk; liver/kidney/stomach/reproductive system problems
• Monitoring Requirements/Comments: For SOCs: Four consecutive quarterly samples during first compliance period. Compliance is based on annual average of quarterly samples. If no detections are found during initial round, two quarterly samples are required each year for systems serving > 3,300; one sample is required every 3 years for smaller systems. With the completion of source water assessments, primacy agencies are allowed to develop alternative monitoring requirements. Contact your local primacy agency for further information. Applies to CWS and NTNCWS.

Glyphosate

• MCL/MCLG (mg/L unless noted): 0.7/0.7
• Health Effects: Kidney/reproductive system problems
• Monitoring Requirements/Comments: For SOCs: Four consecutive quarterly samples during first compliance period. Compliance is based on annual average of quarterly samples. If no detections are found during initial round, two quarterly samples are required each year for systems serving > 3,300; one sample is required every 3 years for smaller systems. With the completion of source water assessments, primacy agencies are allowed to develop alternative monitoring requirements. Contact your local primacy agency for further information. Applies to CWS and NTNCWS.

Heptachlor

• MCL/MCLG (mg/L unless noted): 0.0004/0
• Health Effects: Cancer risk; liver problems
• Monitoring Requirements/Comments: For SOCs: Four consecutive quarterly samples during first compliance period. Compliance is based on annual average of quarterly samples. If no detections are found during initial round, two quarterly samples are required each year for systems serving > 3,300; one sample is required every 3 years for smaller systems. With the completion of source water assessments, primacy agencies are allowed to develop alternative monitoring requirements. Contact your local primacy agency for further information. Applies to CWS and NTNCWS.

Heptachlor Epoxide

• MCL/MCLG (mg/L unless noted): 0.0002/0
• Health Effects: Cancer risk; liver problems
• Monitoring Requirements/Comments: For SOCs: Four consecutive quarterly samples during first compliance period. Compliance is based on annual average of quarterly samples. If no detections are found during initial round, two quarterly samples are required each year for systems serving > 3,300; one sample is required every 3 years for smaller systems. With the completion of source water assessments, primacy agencies are allowed to develop alternative monitoring requirements. Contact your local primacy agency for further information. Applies to CWS and NTNCWS.

Hexachlorobenzene

• MCL/MCLG (mg/L unless noted): 0.001/0
• Health Effects: Cancer risk; liver/reproductive system problems
• Monitoring Requirements/Comments: For SOCs: Four consecutive quarterly samples during first compliance period. Compliance is based on annual average of quarterly samples. If no detections are found during initial round, two quarterly samples are required each year for systems serving > 3,300; one sample is required every 3 years for smaller systems. With the completion of source water assessments, primacy agencies are allowed to develop alternative monitoring requirements. Contact your local primacy agency for further information. Applies to CWS and NTNCWS.

Hexachlorocyclopentadiene (HEX)

• MCL/MCLG (mg/L unless noted): 0.05/0.05
• Health Effects: Kidney/stomach problems
• Monitoring Requirements/Comments: For SOCs: Four consecutive quarterly samples during first compliance period. Compliance is based on annual average of quarterly samples. If no detections are found during initial round, two quarterly samples are required each year for systems serving > 3,300; one sample is required every 3 years for smaller systems. With the completion of source water assessments, primacy agencies are allowed to develop alternative monitoring requirements. Contact your local primacy agency for further information. Applies to CWS and NTNCWS.

Lindane

• MCL/MCLG (mg/L unless noted): 0.0002/0.0002
• Health Effects: Kidney/liver problems
• Monitoring Requirements/Comments: For SOCs: Four consecutive quarterly samples during first compliance period. Compliance is based on annual average of quarterly samples. If no detections are found during initial round, two quarterly samples are required each year for systems serving > 3,300; one sample is required every 3 years for smaller systems. With the completion of source water assessments, primacy agencies are allowed to develop alternative monitoring requirements. Contact your local primacy agency for further information. Applies to CWS and NTNCWS.

Methoxychlor

• MCL/MCLG (mg/L unless noted): 0.04/0.04
• Health Effects: Reproductive system problems
• Monitoring Requirements/Comments: For SOCs: Four consecutive quarterly samples during first compliance period. Compliance is based on annual average of quarterly samples. If no detections are found during initial round, two quarterly samples are required each year for systems serving > 3,300; one sample is required every 3 years for smaller systems. With the completion of source water assessments, primacy agencies are allowed to develop alternative monitoring requirements. Contact your local primacy agency for further information. Applies to CWS and NTNCWS.

Oxamyl (Vydate)

• MCL/MCLG (mg/L unless noted): 0.2/0.2
• Health Effects: Nervous system problems
• Monitoring Requirements/Comments: For SOCs: Four consecutive quarterly samples during first compliance period. Compliance is based on annual average of quarterly samples. If no detections are found during initial round, two quarterly samples are required each year for systems serving > 3,300; one sample is required every 3 years for smaller systems. With the completion of source water assessments, primacy agencies are allowed to develop alternative monitoring requirements. Contact your local primacy agency for further information. Applies to CWS and NTNCWS.

Benzo(a)pyrene (PAHs)

• MCL/MCLG (mg/L unless noted): 0.0002/0
• Health Effects: Cancer risk; reproductive system problems
• Monitoring Requirements/Comments: For SOCs: Four consecutive quarterly samples during first compliance period. Compliance is based on annual average of quarterly samples. If no detections are found during initial round, two quarterly samples are required each year for systems serving > 3,300; one sample is required every 3 years for smaller systems. With the completion of source water assessments, primacy agencies are allowed to develop alternative monitoring requirements. Contact your local primacy agency for further information. Applies to CWS and NTNCWS.

Polychlorinated Biphenyls (PCBs)

• MCL/MCLG (mg/L unless noted): 0.0005/0
• Health Effects: Cancer risk; thymus gland/immune deficiencies/reproductive or nervous system problems
• Monitoring Requirements/Comments: For SOCs: Four consecutive quarterly samples during first compliance period. Compliance is based on annual average of quarterly samples. If no detections are found during initial round, two quarterly samples are required each year for systems serving > 3,300; one sample is required every 3 years for smaller systems. With the completion of source water assessments, primacy agencies are allowed to develop alternative monitoring requirements. Contact your local primacy agency for further information. Applies to CWS and NTNCWS.

Pentachlorophenol

• MCL/MCLG (mg/L unless noted): 0.001/0
• Health Effects: Cancer risk; liver/kidney problems
• Monitoring Requirements/Comments: For SOCs: Four consecutive quarterly samples during first compliance period. Compliance is based on annual average of quarterly samples. If no detections are found during initial round, two quarterly samples are required each year for systems serving > 3,300; one sample is required every 3 years for smaller systems. With the completion of source water assessments, primacy agencies are allowed to develop alternative monitoring requirements. Contact your local primacy agency for further information. Applies to CWS and NTNCWS.

Picloram

• MCL/MCLG (mg/L unless noted): 0.5/0.5
• Health Effects: Liver problems
• Monitoring Requirements/Comments: For SOCs: Four consecutive quarterly samples during first compliance period. Compliance is based on annual average of quarterly samples. If no detections are found during initial round, two quarterly samples are required each year for systems serving > 3,300; one sample is required every 3 years for smaller systems. With the completion of source water assessments, primacy agencies are allowed to develop alternative monitoring requirements. Contact your local primacy agency for further information. Applies to CWS and NTNCWS.

Simazine

• MCL/MCLG (mg/L unless noted): 0.004/0.004
• Health Effects: Problems with blood
• Monitoring Requirements/Comments: For SOCs: Four consecutive quarterly samples during first compliance period. Compliance is based on annual average of quarterly samples. If no detections are found during initial round, two quarterly samples are required each year for systems serving > 3,300; one sample is required every 3 years for smaller systems. With the completion of source water assessments, primacy agencies are allowed to develop alternative monitoring requirements. Contact your local primacy agency for further information. Applies to CWS and NTNCWS.

Toxaphene

• MCL/MCLG (mg/L unless noted): 0.003/0
• Health Effects: Cancer risk; liver/kidney/thyroid problems
• Monitoring Requirements/Comments: For SOCs: Four consecutive quarterly samples during first compliance period. Compliance is based on annual average of quarterly samples. If no detections are found during initial round, two quarterly samples are required each year for systems serving > 3,300; one sample is required every 3 years for smaller systems. With the completion of source water assessments, primacy agencies are allowed to develop alternative monitoring requirements. Contact your local primacy agency for further information. Applies to CWS and NTNCWS.

1,1,1-Trichloroethane

• MCL/MCLG (mg/L unless noted): 0.2/0.20
• Health Effects: Liver/circulatory/nervous system problems
• Monitoring Requirements/Comments: For VOCs: Four consecutive quarterly samples during first compliance period. Compliance is based on annual average of quarterly samples. If no detections are found during initial round, two quarterly samples are required each year for systems serving > 3,300; one sample is required every 3 years for smaller systems. With the completion of source water assessments, primacy agencies are allowed to develop alternative monitoring requirements. Contact your local primacy agency for further information. Applies to CWS and NTNCWS.

1,1,2-Trichloroethane

• MCL/MCLG (mg/L unless noted): 0.005/0.003
• Health Effects: Kidney/liver/immune system problems
• Monitoring Requirements/Comments: For VOCs: Four consecutive quarterly samples during first compliance period. Compliance is based on annual average of quarterly samples. If no detections are found during initial round, two quarterly samples are required each year for systems serving > 3,300; one sample is required every 3 years for smaller systems. With the completion of source water assessments, primacy agencies are allowed to develop alternative monitoring requirements. Contact your local primacy agency for further information. Applies to CWS and NTNCWS.

1,1-Dichloroethylene

• MCL/MCLG (mg/L unless noted): 0.007/0.007
• Health Effects: Liver problems
• Monitoring Requirements/Comments: For VOCs: Four consecutive quarterly samples during first compliance period. Compliance is based on annual average of quarterly samples. If no detections are found during initial round, two quarterly samples are required each year for systems serving > 3,300; one sample is required every 3 years for smaller systems. With the completion of source water assessments, primacy agencies are allowed to develop alternative monitoring requirements. Contact your local primacy agency for further information. Applies to CWS and NTNCWS.

1,2,4-Trichlorobenzene

• MCL/MCLG (mg/L unless noted): 0.07/0.07
• Health Effects: Adrenal gland problems
• Monitoring Requirements/Comments: For VOCs: Four consecutive quarterly samples during first compliance period. Compliance is based on annual average of quarterly samples. If no detections are found during initial round, two quarterly samples are required each year for systems serving > 3,300; one sample is required every 3 years for smaller systems. With the completion of source water assessments, primacy agencies are allowed to develop alternative monitoring requirements. Contact your local primacy agency for further information. Applies to CWS and NTNCWS.

1,2-Dichloroethane

• MCL/MCLG (mg/L unless noted): 0.005/0
• Health Effects: Cancer risk
• Monitoring Requirements/Comments: For VOCs: Four consecutive quarterly samples during first compliance period. Compliance is based on annual average of quarterly samples. If no detections are found during initial round, two quarterly samples are required each year for systems serving > 3,300; one sample is required every 3 years for smaller systems. With the completion of source water assessments, primacy agencies are allowed to develop alternative monitoring requirements. Contact your local primacy agency for further information. Applies to CWS and NTNCWS.

1,2-Dichloropropane

• MCL/MCLG (mg/L unless noted): 0.005/0
• Health Effects: Cancer risk
• Monitoring Requirements/Comments: For VOCs: Four consecutive quarterly samples during first compliance period. Compliance is based on annual average of quarterly samples. If no detections are found during initial round, two quarterly samples are required each year for systems serving > 3,300; one sample is required every 3 years for smaller systems. With the completion of source water assessments, primacy agencies are allowed to develop alternative monitoring requirements. Contact your local primacy agency for further information. Applies to CWS and NTNCWS.

Benzene

• MCL/MCLG (mg/L unless noted): 0.005/0
• Health Effects: Cancer risk; anemia/blood problems
• Monitoring Requirements/Comments: For VOCs: Four consecutive quarterly samples during first compliance period. Compliance is based on annual average of quarterly samples. If no detections are found during initial round, two quarterly samples are required each year for systems serving > 3,300; one sample is required every 3 years for smaller systems. With the completion of source water assessments, primacy agencies are allowed to develop alternative monitoring requirements. Contact your local primacy agency for further information. Applies to CWS and NTNCWS.

Carbon Tetrachloride

• MCL/MCLG (mg/L unless noted): 0.005/0
• Health Effects: Cancer risk; liver problems
• Monitoring Requirements/Comments: For VOCs: Four consecutive quarterly samples during first compliance period. Compliance is based on annual average of quarterly samples. If no detections are found during initial round, two quarterly samples are required each year for systems serving > 3,300; one sample is required every 3 years for smaller systems. With the completion of source water assessments, primacy agencies are allowed to develop alternative monitoring requirements. Contact your local primacy agency for further information. Applies to CWS and NTNCWS.

Chlorobenzene

• MCL/MCLG (mg/L unless noted): 0.1/0.1
• Health Effects: Kidney/liver problems
• Monitoring Requirements/Comments: For VOCs: Four consecutive quarterly samples during first compliance period. Compliance is based on annual average of quarterly samples. If no detections are found during initial round, two quarterly samples are required each year for systems serving > 3,300; one sample is required every 3 years for smaller systems. With the completion of source water assessments, primacy agencies are allowed to develop alternative monitoring requirements. Contact your local primacy agency for further information. Applies to CWS and NTNCWS.

Cis-1,2-Dichloroethylene

• MCL/MCLG (mg/L unless noted): 0.07/0.07
• Health Effects: Liver problems
• Monitoring Requirements/Comments: For VOCs: Four consecutive quarterly samples during first compliance period. Compliance is based on annual average of quarterly samples. If no detections are found during initial round, two quarterly samples are required each year for systems serving > 3,300; one sample is required every 3 years for smaller systems. With the completion of source water assessments, primacy agencies are allowed to develop alternative monitoring requirements. Contact your local primacy agency for further information. Applies to CWS and NTNCWS.

Dichloromethane

• MCL/MCLG (mg/L unless noted): 0.005/0
• Health Effects: Cancer risk; liver problems
• Monitoring Requirements/Comments: For VOCs: Four consecutive quarterly samples during first compliance period. Compliance is based on annual average of quarterly samples. If no detections are found during initial round, two quarterly samples are required each year for systems serving > 3,300; one sample is required every 3 years for smaller systems. With the completion of source water assessments, primacy agencies are allowed to develop alternative monitoring requirements. Contact your local primacy agency for further information. Applies to CWS and NTNCWS.

Ethylbenzene

• MCL/MCLG (mg/L unless noted): 0.7/0.7
• Health Effects: Kidney/liver problems
• Monitoring Requirements/Comments: For VOCs: Four consecutive quarterly samples during first compliance period. Compliance is based on annual average of quarterly samples. If no detections are found during initial round, two quarterly samples are required each year for systems serving > 3,300; one sample is required every 3 years for smaller systems. With the completion of source water assessments, primacy agencies are allowed to develop alternative monitoring requirements. Contact your local primacy agency for further information. Applies to CWS and NTNCWS.

Ortho-Dichlorobenzene

• MCL/MCLG (mg/L unless noted): 0.6/0.6
• Health Effects: Kidney/liver/circulatory system problems
• Monitoring Requirements/Comments: For VOCs: Four consecutive quarterly samples during first compliance period. Compliance is based on annual average of quarterly samples. If no detections are found during initial round, two quarterly samples are required each year for systems serving > 3,300; one sample is required every 3 years for smaller systems. With the completion of source water assessments, primacy agencies are allowed to develop alternative monitoring requirements. Contact your local primacy agency for further information. Applies to CWS and NTNCWS.

Para-Dichlorobenzene

• MCL/MCLG (mg/L unless noted): 0.075/0.075
• Health Effects: Kidney/liver/spleen/circulatory system problems
• Monitoring Requirements/Comments: For VOCs: Four consecutive quarterly samples during first compliance period. Compliance is based on annual average of quarterly samples. If no detections are found during initial round, two quarterly samples are required each year for systems serving > 3,300; one sample is required every 3 years for smaller systems. With the completion of source water assessments, primacy agencies are allowed to develop alternative monitoring requirements. Contact your local primacy agency for further information. Applies to CWS and NTNCWS.

Styrene

• MCL/MCLG (mg/L unless noted): 0.1/0.1
• Health Effects: Liver/kidney/circulatory system problems
• Monitoring Requirements/Comments: For VOCs: Four consecutive quarterly samples during first compliance period. Compliance is based on annual average of quarterly samples. If no detections are found during initial round, two quarterly samples are required each year for systems serving > 3,300; one sample is required every 3 years for smaller systems. With the completion of source water assessments, primacy agencies are allowed to develop alternative monitoring requirements. Contact your local primacy agency for further information. Applies to CWS and NTNCWS.

Tetrachloroethylene (PCE)

• MCL/MCLG (mg/L unless noted): 0.005/0
• Health Effects: Cancer risk; liver problems
• Monitoring Requirements/Comments: For VOCs: Four consecutive quarterly samples during first compliance period. Compliance is based on annual average of quarterly samples. If no detections are found during initial round, two quarterly samples are required each year for systems serving > 3,300; one sample is required every 3 years for smaller systems. With the completion of source water assessments, primacy agencies are allowed to develop alternative monitoring requirements. Contact your local primacy agency for further information. Applies to CWS and NTNCWS.

Toluene

• MCL/MCLG (mg/L unless noted): 1/1
• Health Effects: Kidney/liver/nervous system problems
• Monitoring Requirements/Comments: For VOCs: Four consecutive quarterly samples during first compliance period. Compliance is based on annual average of quarterly samples. If no detections are found during initial round, two quarterly samples are required each year for systems serving > 3,300; one sample is required every 3 years for smaller systems. With the completion of source water assessments, primacy agencies are allowed to develop alternative monitoring requirements. Contact your local primacy agency for further information. Applies to CWS and NTNCWS.

Trans-1,2-Dichloroethylene

• MCL/MCLG (mg/L unless noted): 0.1/0.1
• Health Effects: Liver problems
• Monitoring Requirements/Comments: For VOCs: Four consecutive quarterly samples during first compliance period. Compliance is based on annual average of quarterly samples. If no detections are found during initial round, two quarterly samples are required each year for systems serving > 3,300; one sample is required every 3 years for smaller systems. With the completion of source water assessments, primacy agencies are allowed to develop alternative monitoring requirements. Contact your local primacy agency for further information. Applies to CWS and NTNCWS.

Trichloroethylene (TCE)

• MCL/MCLG (mg/L unless noted): 0.005/0
• Health Effects: Cancer risk; liver problems
• Monitoring Requirements/Comments: For VOCs: Four consecutive quarterly samples during first compliance period. Compliance is based on annual average of quarterly samples. If no detections are found during initial round, two quarterly samples are required each year for systems serving > 3,300; one sample is required every 3 years for smaller systems. With the completion of source water assessments, primacy agencies are allowed to develop alternative monitoring requirements. Contact your local primacy agency for further information. Applies to CWS and NTNCWS.

Vinyl Chloride

• MCL/MCLG (mg/L unless noted): 0.002/0
• Health Effects: Cancer risk
• Monitoring Requirements/Comments: For VOCs: Four consecutive quarterly samples during first compliance period. Compliance is based on annual average of quarterly samples. If no detections are found during initial round, two quarterly samples are required each year for systems serving > 3,300; one sample is required every 3 years for smaller systems. With the completion of source water assessments, primacy agencies are allowed to develop alternative monitoring requirements. Contact your local primacy agency for further information. Applies to CWS and NTNCWS.

Xylenes (total)

• MCL/MCLG (mg/L unless noted): 10/10
• Health Effects: Nervous system problems
• Monitoring Requirements/Comments: For VOCs: Four consecutive quarterly samples during first compliance period. Compliance is based on annual average of quarterly samples. If no detections are found during initial round, two quarterly samples are required each year for systems serving > 3,300; one sample is required every 3 years for smaller systems. With the completion of source water assessments, primacy agencies are allowed to develop alternative monitoring requirements. Contact your local primacy agency for further information. Applies to CWS and NTNCWS.

Total Coliforms (Total Coliform Rule)

• MCL/MCLG (mg/L unless noted): MCL = See comments MCLG = 0 for all 3 indicators
• Health Effects: Coliforms are bacteria that are naturally present in the environment and are used as an indicator that other, potentially harmful, bacteria may be present. The presence of fecal coliform or E.coli may indicate potential contamination that can cause diarrhea, cramps, nausea, headaches or other symptoms.
• Monitoring Requirements/Comments: Applies to all surface water and ground water systems. The total number and location of samples is based on the population served and a system-specific sampling plan. If 40 samples or more/month, no more than 5.0% positive; < 40 samples/month, no more than one positive for total coliforms.

Total Coliform Rule: Total Coliforms

• MCL/MCLG (mg/L unless noted): MCL = See comments MCLG = 0 for all 3 indicators
• Health Effects: Coliforms are bacteria that are naturally present in the environment and are used as an indicator that other, potentially harmful bacteria may be present. The presence of fecal coliform or E.coli may indicate potential contamination that can cause diarrhea, cramps, nausea, headaches or other symptoms.
• Monitoring Requirements/Comments: Applies to all surface water and ground water systems. The total number and location of samples is based on the population served and a system-specific sampling plan. If 40 samples or more/month, no more than 5.0% positive; < 40 samples/month, no more than one positive for total coliforms.

Fecal Coliforms (Total Coliform Rule)

• MCL/MCLG (mg/L unless noted): MCL = See comments MCLG = 0 for all 3 indicators
• Health Effects: Coliforms are bacteria that are naturally present in the environment and are used as an indicator that other, potentially harmful bacteria may be present. The presence of fecal coliform or E.coli may indicate potential contamination that can cause diarrhea, cramps, nausea, headaches or other symptoms.
• Monitoring Requirements/Comments: Applies to all surface water and ground water systems. The total number and location of samples is based on the population served and a system-specific sampling plan. If 40 samples or more/month, no more than 5.0% positive; < 40 samples/month, no more than one positive for total coliforms.

Total Coliform Rule: Fecal Coliforms

• MCL/MCLG (mg/L unless noted): MCL = See comments MCLG = 0 for all 3 indicators
• Health Effects: Coliforms are bacteria that are naturally present in the environment and are used as an indicator that other, potentially harmful bacteria may be present. The presence of fecal coliform or E.coli may indicate potential contamination that can cause diarrhea, cramps, nausea, headaches or other symptoms.
• Monitoring Requirements/Comments: Applies to all surface water and ground water systems. The total number and location of samples is based on the population served and a system-specific sampling plan. If 40 samples or more/month, no more than 5.0% positive; < 40 samples/month, no more than one positive for total coliforms.

E. coli (Total Coliform Rule)

• MCL/MCLG (mg/L unless noted): MCL = See comments MCLG = 0 for all 3 indicators
• Health Effects: Coliforms are bacteria that are naturally present in the environment and are used as an indicator that other, potentially harmful bacteria may be present. The presence of fecal coliform or E.coli may indicate potential contamination that can cause diarrhea, cramps, nausea, headaches or other symptoms.
• Monitoring Requirements/Comments: Proposed RTCR published on July 14, 2010. E. coli MCL violation when i) both routine and associated repeat TC samples are TC-positive and either is also E. coli-positive, or ii) when system fails to take required repeat samples after routine sample is TC- and E. coli-positive. Monitoring for systems >1,000 remains the same except for changes to repeat and additional routine monitoring. TC-positives used as an indicator to start evaluation process to identify and correct sanitary defects. Level 1 assessment triggered by exceeding 5.0% TC-positives per month (systems taking ≥ 40 samples), by two or more TC-positives per month (systems taking < 40 samples), or by failing to take repeat samples. Level 2 assessment triggered by E. coli MCL violation, E. coli monitoring violation or second Level 1 trigger within a 12 month rolling period. Final RTCR is scheduled for promulgation in 2012.

Total Coliform Rule: E. coli

• MCL/MCLG (mg/L unless noted): MCL = See comments MCLG = 0 for all 3 indicators
• Health Effects: Coliforms are bacteria that are naturally present in the environment and are used as an indicator that other, potentially harmful bacteria may be present. The presence of fecal coliform or E.coli may indicate potential contamination that can cause diarrhea, cramps, nausea, headaches or other symptoms.
• Monitoring Requirements/Comments: Proposed RTCR published on July 14, 2010. E. coli MCL violation when i) both routine and associated repeat TC samples are TC-positive and either is also E. coli-positive, or ii) when system fails to take required repeat samples after routine sample is TC- and E. coli-positive. Monitoring for systems >1,000 remains the same except for changes to repeat and additional routine monitoring. TC-positives used as an indicator to start evaluation process to identify and correct sanitary defects. Level 1 assessment triggered by exceeding 5.0% TC-positives per month (systems taking ≥ 40 samples), by two or more TC-positives per month (systems taking < 40 samples), or by failing to take repeat samples. Level 2 assessment triggered by E. coli MCL violation, E. coli monitoring violation or second Level 1 trigger within a 12 month rolling period. Final RTCR is scheduled for promulgation in 2012.

Turbidity (SWTR)

• MCL/MCLG (mg/L unless noted): TT
• Health Effects: None. Interferes with disinfection.
• Monitoring Requirements/Comments: Applies to all public water systems using surface water or ground water under the direct infl uence of surface water. Grab samples every four hours or continuous monitoring for turbidity. Continuous chlorine residual required for systems > 3,300; one to four grab samples per day for systems ≤ 3,300. Must maintain disinfectant residual ≥ 0.2 mg/L at distribution system entry. Performance requirements demonstrated through combination of removal (filtration) and inactivation (disinfection). See IESWTR and LT1ESWTR for turbidity TT requirements.

SWTR: Turbidity

• MCL/MCLG (mg/L unless noted): TT
• Health Effects: None. Interferes with disinfection.
• Monitoring Requirements/Comments: Applies to all public water systems using surface water or ground water under the direct infl uence of surface water. Grab samples every four hours or continuous monitoring for turbidity. Continuous chlorine residual required for systems > 3,300; one to four grab samples per day for systems ≤ 3,300. Must maintain disinfectant residual ≥ 0.2 mg/L at distribution system entry. Performance requirements demonstrated through combination of removal (filtration) and inactivation (disinfection). See IESWTR and LT1ESWTR for turbidity TT requirements.

Giardia lamblia (SWTR)

• MCL/MCLG (mg/L unless noted): TT/0
• Health Effects: Gastrointestinal illness; Giardiasis
• Monitoring Requirements/Comments: Minimum three-log removal/inactivation of Giardia (99.9%).

SWTR: Giardia lamblia

• MCL/MCLG (mg/L unless noted): TT/0
• Health Effects: Gastrointestinal illness; Giardiasis
• Monitoring Requirements/Comments: Minimum three-log removal/inactivation of Giardia (99.9%).

Enteric Viruses (SWTR)

• MCL/MCLG (mg/L unless noted): TT/0
• Health Effects: Gastrointestinal and other viral infections
• Monitoring Requirements/Comments: Minimum four-log removal/inactivation of viruses (99.99%).

SWTR: Enteric Viruses

• MCL/MCLG (mg/L unless noted): TT/0
• Health Effects: Gastrointestinal and other viral infections
• Monitoring Requirements/Comments: Minimum four-log removal/inactivation of viruses (99.99%).

Legionella (SWTR)

• MCL/MCLG (mg/L unless noted): TT/0
• Health Effects: Legionnaire's disease
• Monitoring Requirements/Comments: No limit. Rule assumes if virus & Giardia limits are met, Legionella will be controlled.

SWTR: Legionella

• MCL/MCLG (mg/L unless noted): TT/0
• Health Effects: Legionnaire's disease
• Monitoring Requirements/Comments: No limit. Rule assumes if virus & Giardia limits are met, Legionella will be controlled.

Heterotrophic Plate Count - HPC (SWTR)

• MCL/MCLG (mg/L unless noted): TT
• Health Effects: None. Used to measure variety of bacteria common in water.
• Monitoring Requirements/Comments: Filtration avoidance is allowed under certain circumstances (see Regulation). Lower bacteria concentration indicates better maintained water system.

SWTR: Heterotrophic Plate Count (HPC)

• MCL/MCLG (mg/L unless noted): TT
• Health Effects: None. Used to measure variety of bacteria common in water.
• Monitoring Requirements/Comments: Filtration avoidance is allowed under certain circumstances (see Regulation). Lower bacteria concentration indicates better maintained water system.

Turbidity (IESWTR)

• MCL/MCLG (mg/L unless noted): TT
• Health Effects: None. Interferes with disinfection.
• Monitoring Requirements/Comments: Applies to plants using surface water or ground water under the direct influence of surface water. Must continue to comply with SWTR. Treatment effectiveness is demonstrated by combined effluent turbidity = 0.3 NTU in 95% of measurements taken each month. Conventional and direct filtration systems must measure combined filter effluent turbidity at least every four hours and continuously monitor turbidity of each individual filter. The maximum turbidity limit is 1 NTU. If the PWS meets filtered water turbidity criteria, it is assumed to achieve the required 2-log Cryptosporidium removal. Performance triggers for individual filter turbidities lead to additional reporting and assessments if exceeded. IESWTR applies to systems = 10,000; LT1ESWTR applies to systems <10,000 people.

IESWTR: Turbidity

• MCL/MCLG (mg/L unless noted): TT
• Health Effects: None. Interferes with disinfection.
• Monitoring Requirements/Comments: Applies to plants using surface water or ground water under the direct influence of surface water. Must continue to comply with SWTR. Treatment effectiveness is demonstrated by combined effluent turbidity = 0.3 NTU in 95% of measurements taken each month. Conventional and direct filtration systems must measure combined filter effluent turbidity at least every four hours and continuously monitor turbidity of each individual filter. The maximum turbidity limit is 1 NTU. If the PWS meets filtered water turbidity criteria, it is assumed to achieve the required 2-log Cryptosporidium removal. Performance triggers for individual filter turbidities lead to additional reporting and assessments if exceeded. IESWTR applies to systems = 10,000; LT1ESWTR applies to systems <10,000 people.

Cryptosporidium (IESWTR)

• MCL/MCLG (mg/L unless noted): TT/0
• Health Effects: Gastrointestinal illness; Cryptosporidiosis
• Monitoring Requirements/Comments: Applies to plants using surface water or ground water under the direct influence of surface water. Must continue to comply with SWTR. Treatment effectiveness is demonstrated by combined effluent turbidity = 0.3 NTU in 95% of measurements taken each month. Conventional and direct filtration systems must measure combined filter effluent turbidity at least every four hours and continuously monitor turbidity of each individual filter. The maximum turbidity limit is 1 NTU. If the PWS meets filtered water turbidity criteria, it is assumed to achieve the required 2-log Cryptosporidium removal. Performance triggers for individual filter turbidities lead to additional reporting and assessments if exceeded. IESWTR applies to systems = 10,000; LT1ESWTR applies to systems <10,000 people.

IESWTR: Cryptosporidium

• MCL/MCLG (mg/L unless noted): TT/0
• Health Effects: Gastrointestinal illness; Cryptosporidiosis
• Monitoring Requirements/Comments: Applies to plants using surface water or ground water under the direct influence of surface water. Must continue to comply with SWTR. Treatment effectiveness is demonstrated by combined effluent turbidity = 0.3 NTU in 95% of measurements taken each month. Conventional and direct filtration systems must measure combined filter effluent turbidity at least every four hours and continuously monitor turbidity of each individual filter. The maximum turbidity limit is 1 NTU. If the PWS meets filtered water turbidity criteria, it is assumed to achieve the required 2-log Cryptosporidium removal. Performance triggers for individual filter turbidities lead to additional reporting and assessments if exceeded. IESWTR applies to systems = 10,000; LT1ESWTR applies to systems <10,000 people.

Cryptosporidium (Filter Backwash Rule)

• MCL/MCLG (mg/L unless noted): TT/0
• Health Effects: Gastrointestinal illness; Cryptosporidiosis
• Monitoring Requirements/Comments: No monitoring is required, but systems must collect and retain information on recycle flows for review by the primacy agency. Applies to all systems using conventional or direct filtration treatment that recycle spent filter backwash water (excluding membrane plants), thickener supernatant or liquids from dewatering processes. TT Requirement - All recycle flows must be returned at the head of the plant so that complete treatment of the recycle stream is provided. Treatment of recycle streams prior to recycle is not required.

Filter Backwash Rule: Cryptosporidium

• MCL/MCLG (mg/L unless noted): TT/0
• Health Effects: Gastrointestinal illness; Cryptosporidiosis
• Monitoring Requirements/Comments: No monitoring is required, but systems must collect and retain information on recycle flows for review by the primacy agency. Applies to all systems using conventional or direct filtration treatment that recycle spent filter backwash water (excluding membrane plants), thickener supernatant or liquids from dewatering processes. TT Requirement - All recycle flows must be returned at the head of the plant so that complete treatment of the recycle stream is provided. Treatment of recycle streams prior to recycle is not required.

Turbidity (LT1ESWTR)

• MCL/MCLG (mg/L unless noted): TT
• Health Effects: None. Interferes with disinfection.
• Monitoring Requirements/Comments: Applies to plants using surface water or ground water under the direct influence of surface water. Must continue to comply with SWTR. Treatment effectiveness is demonstrated by combined effluent turbidity = 0.3 NTU in 95% of measurements taken each month. Conventional and direct filtration systems must measure combined filter effluent turbidity at least every four hours and continuously monitor turbidity of each individual filter. The maximum turbidity limit is 1 NTU. If the PWS meets filtered water turbidity criteria, it is assumed to achieve the required 2-log Cryptosporidium removal. Performance triggers for individual filter turbidities lead to additional reporting and assessments if exceeded. IESWTR applies to systems = 10,000; LT1ESWTR applies to systems <10,000 people.

LT1ESWTR: Turbidity

• MCL/MCLG (mg/L unless noted): TT
• Health Effects: None. Interferes with disinfection.
• Monitoring Requirements/Comments: Applies to plants using surface water or ground water under the direct influence of surface water. Must continue to comply with SWTR. Treatment effectiveness is demonstrated by combined effluent turbidity = 0.3 NTU in 95% of measurements taken each month. Conventional and direct filtration systems must measure combined filter effluent turbidity at least every four hours and continuously monitor turbidity of each individual filter. The maximum turbidity limit is 1 NTU. If the PWS meets filtered water turbidity criteria, it is assumed to achieve the required 2-log Cryptosporidium removal. Performance triggers for individual filter turbidities lead to additional reporting and assessments if exceeded. IESWTR applies to systems = 10,000; LT1ESWTR applies to systems <10,000 people.

Cryptosporidium (LT1ESWTR)

• MCL/MCLG (mg/L unless noted): TT/0
• Health Effects: Gastrointestinal illness; Cryptosporidiosis
• Monitoring Requirements/Comments: Applies to plants using surface water or ground water under the direct influence of surface water. Must continue to comply with SWTR. Treatment effectiveness is demonstrated by combined effluent turbidity = 0.3 NTU in 95% of measurements taken each month. Conventional and direct filtration systems must measure combined filter effluent turbidity at least every four hours and continuously monitor turbidity of each individual filter. The maximum turbidity limit is 1 NTU. If the PWS meets filtered water turbidity criteria, it is assumed to achieve the required 2-log Cryptosporidium removal. Performance triggers for individual filter turbidities lead to additional reporting and assessments if exceeded. IESWTR applies to systems = 10,000; LT1ESWTR applies to systems <10,000 people.

LT1ESWTR: Cryptosporidium

• MCL/MCLG (mg/L unless noted): TT/0
• Health Effects: Gastrointestinal illness; Cryptosporidiosis
• Monitoring Requirements/Comments: Applies to plants using surface water or ground water under the direct influence of surface water. Must continue to comply with SWTR. Treatment effectiveness is demonstrated by combined effluent turbidity = 0.3 NTU in 95% of measurements taken each month. Conventional and direct filtration systems must measure combined filter effluent turbidity at least every four hours and continuously monitor turbidity of each individual filter. The maximum turbidity limit is 1 NTU. If the PWS meets filtered water turbidity criteria, it is assumed to achieve the required 2-log Cryptosporidium removal. Performance triggers for individual filter turbidities lead to additional reporting and assessments if exceeded. IESWTR applies to systems = 10,000; LT1ESWTR applies to systems <10,000 people.

Cryptosporidium (LT2ESWTR)

• MCL/MCLG (mg/L unless noted): TT/0
• Health Effects: Gastrointestinal illness; Cryptosporidiosis
• Monitoring Requirements/Comments: Applies to all public water systems using surface water or ground water under the direct influence of surface water. Monthly monitoring for Cryptosporidium for 2 years is required to characterize the source water. Small systems monitor for E.coli in lieu of Cryptosporidium, unless E.coli is high - then monitor for Cryptosporidium. First round of monitoring takes place between 2006 and 2010, staggered by system size. Second round of Cryptosporidium monitoring due 2015-2019, depending on system size. Calculated Cryptosporidium concentration defines required level of additional treatment. Treatment bins differ for filtered and unfiltered systems. Additional treatment options selected from the Microbial Toolbox. Additional treatment must be in place by 2012 for systems > 50,000 and by 2013 or 2014 for smaller systems, depending on size.

LT2ESWTR: Cryptosporidium

• MCL/MCLG (mg/L unless noted): TT/0
• Health Effects: Gastrointestinal illness; Cryptosporidiosis
• Monitoring Requirements/Comments: Applies to all public water systems using surface water or ground water under the direct influence of surface water. Monthly monitoring for Cryptosporidium for 2 years is required to characterize the source water. Small systems monitor for E.coli in lieu of Cryptosporidium, unless E.coli is high - then monitor for Cryptosporidium. First round of monitoring takes place between 2006 and 2010, staggered by system size. Second round of Cryptosporidium monitoring due 2015-2019, depending on system size. Calculated Cryptosporidium concentration defines required level of additional treatment. Treatment bins differ for filtered and unfiltered systems. Additional treatment options selected from the Microbial Toolbox. Additional treatment must be in place by 2012 for systems > 50,000 and by 2013 or 2014 for smaller systems, depending on size.

Viruses

• MCL/MCLG (mg/L unless noted): TT
• Health Effects: Gastrointestinal illness
• Monitoring Requirements/Comments: Applies to all public water systems using surface water or ground water under the direct influence of surface water. Grab samples every four hours or continuous monitoring for turbidity. Continuous chlorine residual required for systems > 3,300; one to four grab samples per day for systems = 3,300. Must maintain disinfectant residual = 0.2 mg/L at distribution system entry. Performance requirements demonstrated through combination of removal (filtration) and inactivation (disinfection). See IESWTR and LT1ESWTR for turbidity TT requirements.

GWR: Viruses

• MCL/MCLG (mg/L unless noted): TT
• Health Effects: Gastrointestinal illness
• Monitoring Requirements/Comments: Applies to all ground water systems. Sanitary surveys required every 3 years for CWS and every 5 years for NCWS. Source water monitoring is required for systems that do not treat to 4-log viral inactivation and is triggered by a total coliform (TC)-positive sample in the distribution system. Samples must be taken within 24 hours of TC-positive at all sources on line at the time the TC sample was taken. Special notification requirements for wholesalers and consecutive systems for TC-positive. If your state identifies significant deficiencies in sanitary survey, corrective action is required and can consist of: correcting deficiencies, providing alternative source of water, eliminating source of contamination or providing treatment for 4-log inactivation of viruses. Implementation of rule varies widely among states – consult with your primacy agency regarding requirements.

Stage 1 D/DBPR Disinfectants

• Monitoring Requirements/Comments: Applies to all CWS and NTNCWS that treat water with a chemical disinfectant for primary or residual treatment.

Chlorine (Stage 1 D/DBPR)

• MCL/MCLG (mg/L unless noted): 4.0 (as Cl2) MRDL/4 MRDLG
• Health Effects: Eye/nose irritation; stomach discomfort
• Monitoring Requirements/Comments: Monitor at the same sample locations as the TCR. Compliance based on running annual arithmetic average of monthly averages. Daily sample at distribution system entry point.

Stage 1 D/DBPR: Chlorine

• MCL/MCLG (mg/L unless noted): 4.0 (as Cl2) MRDL/4 MRDLG
• Health Effects: Eye/nose irritation; stomach discomfort
• Monitoring Requirements/Comments: Monitor at the same sample locations as the TCR. Compliance based on running annual arithmetic average of monthly averages. Daily sample at distribution system entry point.

Chloramines (Stage 1 D/DBPR)

• MCL/MCLG (mg/L unless noted): 4.0 (as Cl2) MRDL/4 MRDLG
• Health Effects: Eye/nose irritation; stomach discomfort; anemia
• Monitoring Requirements/Comments: Monitor at the same sample locations as the TCR. Compliance based on running annual arithmetic average of monthly averages. Daily sample at distribution system entry point.

Stage 1 D/DBPR: Chloramines

• MCL/MCLG (mg/L unless noted): 4.0 (as Cl2) MRDL/4 MRDLG
• Health Effects: Eye/nose irritation; stomach discomfort; anemia
• Monitoring Requirements/Comments: Monitor at the same sample locations as the TCR. Compliance based on running annual arithmetic average of monthly averages. Daily sample at distribution system entry point.

Chlorine Dioxide (Stage 1 D/DBPR)

• MCL/MCLG (mg/L unless noted): 0.8 (as ClO2) MRDL / 0.8 MRDLG
• Health Effects: Anemia; nervous system problems
• Monitoring Requirements/Comments: Daily sample at distribution system entry points. Four quarterly distribution samples. Compliance based on running annual average of quarterly average.

Stage 1 D/DBPR: Chlorine Dioxide

• MCL/MCLG (mg/L unless noted): 0.8 (as ClO2) MRDL / 0.8 MRDLG
• Health Effects: Anemia; nervous system problems
• Monitoring Requirements/Comments: Daily sample at distribution system entry points. Four quarterly distribution samples. Compliance based on running annual average of quarterly average.

Total Trihalomethanes - TTHMs (Stage 1 D/DBPR)

• MCL/MCLG (mg/L unless noted): 0.08
• Health Effects: Cancer risk; potential reproductive system effects; liver/kidney/nervous system problems
• Monitoring Requirements/Comments: Running annual average of quarterly samples at four distribution system sites per plant or entry point.

Stage 1 D/DBPR: Total Trihalomethanes (TTHMs)

• MCL/MCLG (mg/L unless noted): 0.08
• Health Effects: Cancer risk; potential reproductive system effects; liver/kidney/nervous system problems
• Monitoring Requirements/Comments: Running annual average of quarterly samples at four distribution system sites per plant or entry point.

Haloacetic Acids - HAA5 (Stage 1 D/DBPR)

• MCL/MCLG (mg/L unless noted): 0.06
• Health Effects: Cancer risk
• Monitoring Requirements/Comments: Running annual average of quarterly samples at four distribution system sites per plant or entry point.

Stage 1 D/DBPR: Haloacetic Acids (HAA5)

• MCL/MCLG (mg/L unless noted): 0.06
• Health Effects: Cancer risk
• Monitoring Requirements/Comments: Running annual average of quarterly samples at four distribution system sites per plant or entry point.

Chlorite (Stage 1 D/DBPR)

• MCL/MCLG (mg/L unless noted): 1.0/0.8
• Health Effects: Anemia; nervous system problems
• Monitoring Requirements/Comments: Systems that add chlorine dioxide required to take daily sample at distribution system entry point.

Stage 1 D/DBPR: Chlorite

• MCL/MCLG (mg/L unless noted): 1.0/0.8
• Health Effects: Anemia; nervous system problems
• Monitoring Requirements/Comments: Systems that add chlorine dioxide required to take daily sample at distribution system entry point.

Bromate (Stage 1 D/DBPR)

• MCL/MCLG (mg/L unless noted): 0.010/0
• Health Effects: Cancer risk
• Monitoring Requirements/Comments: One sample per month (ozone systems only). Compliance based on running annual average.

Stage 1 D/DBPR: Bromate

• MCL/MCLG (mg/L unless noted): 0.010/0
• Health Effects: Cancer risk
• Monitoring Requirements/Comments: One sample per month (ozone systems only). Compliance based on running annual average.

Total Organic Carbon - TOC (Stage 1 D/DBPR)

• MCL/MCLG (mg/L unless noted): TT
• Monitoring Requirements/Comments: Source and treated water TOC sampled once a month. Compliance based on running annual average of TOC removal ratios.

Stage 1 D/DBPR: Total Organic Carbon (TOC)

• MCL/MCLG (mg/L unless noted): TT
• Monitoring Requirements/Comments: Source and treated water TOC sampled once a month. Compliance based on running annual average of TOC removal ratios.

Total Trihalomethanes - TTHMs (Stage 2 D/DBPR)

• MCL/MCLG (mg/L unless noted): MCL: 0.080 / MCLG: Chloroform (0.07), BDCM (0), DBCM (0.06), Bromoform (0)
• Health Effects: Cancer risk; potential reproductive system effects; liver/kidney/nervous system problems
• Monitoring Requirements/Comments: Compliance Monitoring: Locational Running Annual Average (LRAA) of quarterly samples (yearly for very small surface water and small ground water systems) taken at locations determined by Initial Distribution System Evaluation (IDSE). The number of sites is based on the type of source water and population served. Compliance based on LRAAs is required by 2012-2013, depending on system size.

Stage 2 D/DBPR: Total Trihalomethanes (TTHMs)

• MCL/MCLG (mg/L unless noted): MCL: TTHMs 0.080 / MCLG: Chloroform (0.07), BDCM (0), DBCM (0.06), Bromoform (0)
• Health Effects: Cancer risk; potential reproductive system effects; liver/kidney/nervous system problems
• Monitoring Requirements/Comments: Compliance Monitoring: Locational Running Annual Average (LRAA) of quarterly samples (yearly for very small surface water and small ground water systems) taken at locations determined by Initial Distribution System Evaluation (IDSE). The number of sites is based on the type of source water and population served. Compliance based on LRAAs is required by 2012-2013, depending on system size.

Haloacetic Acids - HAA5 (Stage 2 D/DBPR)

• MCL/MCLG (mg/L unless noted): MCL: HAA5 0.060 / MCLG: MCAA (0.07), DCAA (0), TCAA (0.02)
• Health Effects: Nervous system/liver effects
• Monitoring Requirements/Comments: Compliance Monitoring: Locational Running Annual Average (LRAA) of quarterly samples (yearly for very small surface water and small ground water systems) taken at locations determined by Initial Distribution System Evaluation (IDSE). The number of sites is based on the type of source water and population served. Compliance based on LRAAs is required by 2012-2013, depending on system size.

Stage 2 D/DBPR: Haloacetic Acids (HAA5)

• MCL/MCLG (mg/L unless noted): MCL: 0.060 / MCLG: MCAA (0.07), DCAA (0), TCAA (0.02)
• Health Effects: Nervous system/liver effects
• Monitoring Requirements/Comments: Compliance Monitoring: Locational Running Annual Average (LRAA) of quarterly samples (yearly for very small surface water and small ground water systems) taken at locations determined by Initial Distribution System Evaluation (IDSE). The number of sites is based on the type of source water and population served. Compliance based on LRAAs is required by 2012-2013, depending on system size.

None (data reporting only)

• Monitoring Requirements/Comments: PWS to prepare and distribute annual CCR to their customers every July.

Lead and Copper (Future Regulation)

• MCL/MCLG (mg/L unless noted): Lead: TT (AL = 0.015) / 0; Copper: TT (AL = 1.3) / 0
• Health Effects: Lead: Kidney problems; high blood pressure; infants and children - delays in physical or mental development; Copper: Gastrointestinal/liver/kidney problems
• Monitoring Requirements/Comments: Revisions planned for 2012. Potential changes: Flushing guidance and sample collection after service line replacement, lead service line replacement programs, sample site criteria, corrosion control guidance, tap sampling issues, consecutive water systems.

Total Coliforms (Future Regulation)

• MCL/MCLG (mg/L unless noted): TT (See Comments) MCLG = 0
• Health Effects: Coliforms are bacteria that are naturally present in the environment and are used as an indicator that other, potentially harmful bacteria may be present. The presence of E. coli may indicate potential contamination that can cause diarrhea, cramps, nausea, headaches or other symptoms.
• Monitoring Requirements/Comments: Proposed RTCR published on July 14, 2010. E. coli MCL violation when i) both routine and associated repeat TC samples are TC-positive and either is also E. coli-positive, or ii) when system fails to take required repeat samples after routine sample is TC- and E. coli-positive. Monitoring for systems >1,000 remains the same except for changes to repeat and additional routine monitoring. TC-positives used as an indicator to start evaluation process to identify and correct sanitary defects. Level 1 assessment triggered by exceeding 5.0% TC-positives per month (systems taking ≥ 40 samples), by two or more TC-positives per month (systems taking < 40 samples), or by failing to take repeat samples. Level 2 assessment triggered by E. coli MCL violation, E. coli monitoring violation or second Level 1 trigger within a 12 month rolling period. Final RTCR is scheduled for promulgation in 2012.

E.coli (Future Regulation)

• MCL/MCLG (mg/L unless noted): TT (See Comments) MCLG = 0
• Health Effects: Coliforms are bacteria that are naturally present in the environment and are used as an indicator that other, potentially harmful bacteria may be present. The presence of E. coli may indicate potential contamination that can cause diarrhea, cramps, nausea, headaches or other symptoms.
• Monitoring Requirements/Comments: Proposed RTCR published on July 14, 2010. E. coli MCL violation when i) both routine and associated repeat TC samples are TC-positive and either is also E. coli-positive, or ii) when system fails to take required repeat samples after routine sample is TC- and E. coli-positive. Monitoring for systems >1,000 remains the same except for changes to repeat and additional routine monitoring. TC-positives used as an indicator to start evaluation process to identify and correct sanitary defects. Level 1 assessment triggered by exceeding 5.0% TC-positives per month (systems taking = 40 samples), by two or more TC-positives per month (systems taking < 40 samples), or by failing to take repeat samples. Level 2 assessment triggered by E. coli MCL violation, E. coli monitoring violation or second Level 1 trigger within a 12 month rolling period. Final RTCR is scheduled for promulgation in 2012.

Numerous potential groups of contaminants (Future Regulation)

• Monitoring Requirements/Comments: EPA's new drinking water strategy includes regulating contaminants as groups. Groups for consideration include carcinogenic volatile organic chemicals (VOCs), nitrosamines, disinfection byproducts from chlorination, perfluoronated compounds (PFCs), organophosphates, carbamates, triazines, chloracetanilides and cyanotoxins. The EPA is expected to select one group for regulation by early 2011. The EPA believes it has enough information to make a decision for the first three groups listed, but needs more data for the other groups.

Fluoride (Future Regulation)

• MCL/MCLG (mg/L unless noted): To be determined
• Health Effects: Bone disease; children may get mottled teeth
• Monitoring Requirements/Comments: The US Department of Health and Human Services has requested comment on lowering the recommended level of fluoride to 0.7 mg/L. The EPA intends to consider tightening the MCL but no schedule has been established.

Perchlorate (Future Regulation)

• MCL/MCLG (mg/L unless noted): To be determined
• Health Effects: Prevents the thyroid gland from absorbing iodide from the bloodstream, a process known as inhibiting iodide uptake.
• Monitoring Requirements/Comments: Regulatory determination not to regulate (2008) has been reopened after the EPA published a supplemental request for comment on the breakdown of the Health Reference Levels (HRLs) by age category and EPA's finding of substantial likelihood that perchlorate will occur in public water systems with a frequency and at levels of public health concern. HRLs of various life stages range from 2 ppb to 23 ppb, so this is the likely range for the proposed MCLG. The EPA's final regulatory determination is expected by early 2011.

Aluminum (Secondary Drinking Water Standards)

• Monitoring Requirements/Comments: National Secondary Drinking Water Standards are non-enforceable guidelines regulating contaminants that may cause cosmetic effects or aesthetic effects in drinking water. The EPA recommends secondary standards but does not require systems to comply with secondary MCLs. States may establish or enforce standards that differ from these recommendations.
• Secondary MCL (mg/L unless noted): 0.05 to 0.2
• Noticeable Effects Above Secondary MCL: Colored water

Chloride (Secondary Drinking Water Standards)

• Monitoring Requirements/Comments: National Secondary Drinking Water Standards are non-enforceable guidelines regulating contaminants that may cause cosmetic effects or aesthetic effects in drinking water. The EPA recommends secondary standards but does not require systems to comply with secondary MCLs. States may establish or enforce standards that differ from these recommendations.
• Secondary MCL (mg/L unless noted): 250
• Noticeable Effects Above Secondary MCL: Salty taste

Color (Secondary Drinking Water Standards)

• Monitoring Requirements/Comments: National Secondary Drinking Water Standards are non-enforceable guidelines regulating contaminants that may cause cosmetic effects or aesthetic effects in drinking water. The EPA recommends secondary standards but does not require systems to comply with secondary MCLs. States may establish or enforce standards that differ from these recommendations.
• Secondary MCL (mg/L unless noted): 15 (color units)
• Noticeable Effects Above Secondary MCL: Visible tint

Copper (Secondary Drinking Water Standards)

• Monitoring Requirements/Comments: National Secondary Drinking Water Standards are non-enforceable guidelines regulating contaminants that may cause cosmetic effects or aesthetic effects in drinking water. The EPA recommends secondary standards but does not require systems to comply with secondary MCLs. States may establish or enforce standards that differ from these recommendations.
• Secondary MCL (mg/L unless noted): 1
• Noticeable Effects Above Secondary MCL: Metallic taste; blue-green staining

Corrosivity (Secondary Drinking Water Standards)

• Monitoring Requirements/Comments: National Secondary Drinking Water Standards are non-enforceable guidelines regulating contaminants that may cause cosmetic effects or aesthetic effects in drinking water. The EPA recommends secondary standards but does not require systems to comply with secondary MCLs. States may establish or enforce standards that differ from these recommendations.
• Secondary MCL (mg/L unless noted): Noncorrosive
• Noticeable Effects Above Secondary MCL: Metallic taste; corroded pipes/ fixtures; staining

Fluoride (Secondary Drinking Water Standards)

• Monitoring Requirements/Comments: National Secondary Drinking Water Standards are non-enforceable guidelines regulating contaminants that may cause cosmetic effects or aesthetic effects in drinking water. The EPA recommends secondary standards but does not require systems to comply with secondary MCLs. States may establish or enforce standards that differ from these recommendations.
• Secondary MCL (mg/L unless noted): 2
• Noticeable Effects Above Secondary MCL: Tooth discoloration

Foaming Agents (Secondary Drinking Water Standards)

• Monitoring Requirements/Comments: National Secondary Drinking Water Standards are non-enforceable guidelines regulating contaminants that may cause cosmetic effects or aesthetic effects in drinking water. The EPA recommends secondary standards but does not require systems to comply with secondary MCLs. States may establish or enforce standards that differ from these recommendations.
• Secondary MCL (mg/L unless noted): 0.5
• Noticeable Effects Above Secondary MCL: Frothy, cloudy; bitter taste; odor

Iron (Secondary Drinking Water Standards)

• Monitoring Requirements/Comments: National Secondary Drinking Water Standards are non-enforceable guidelines regulating contaminants that may cause cosmetic effects or aesthetic effects in drinking water. The EPA recommends secondary standards but does not require systems to comply with secondary MCLs. States may establish or enforce standards that differ from these recommendations.
• Secondary MCL (mg/L unless noted): 0.3
• Noticeable Effects Above Secondary MCL: Rusty color; sediment; metallic taste; reddish or orange staining

Manganese (Secondary Drinking Water Standards)

• Monitoring Requirements/Comments: National Secondary Drinking Water Standards are non-enforceable guidelines regulating contaminants that may cause cosmetic effects or aesthetic effects in drinking water. The EPA recommends secondary standards but does not require systems to comply with secondary MCLs. States may establish or enforce standards that differ from these recommendations.
• Secondary MCL (mg/L unless noted): 0.05
• Noticeable Effects Above Secondary MCL: Black to brown color; black staining; bitter metallic taste

Odor (Secondary Drinking Water Standards)

• Monitoring Requirements/Comments: National Secondary Drinking Water Standards are non-enforceable guidelines regulating contaminants that may cause cosmetic effects or aesthetic effects in drinking water. The EPA recommends secondary standards but does not require systems to comply with secondary MCLs. States may establish or enforce standards that differ from these recommendations.
• Secondary MCL (mg/L unless noted): 3 TON (threshold odor number)
• Noticeable Effects Above Secondary MCL: Rotten-egg, musty or chemical smell

pH (Secondary Drinking Water Standards)

• Monitoring Requirements/Comments: National Secondary Drinking Water Standards are non-enforceable guidelines regulating contaminants that may cause cosmetic effects or aesthetic effects in drinking water. The EPA recommends secondary standards but does not require systems to comply with secondary MCLs. States may establish or enforce standards that differ from these recommendations.
• Secondary MCL (mg/L unless noted): 6.5 - 8.5 su
• Noticeable Effects Above Secondary MCL: Low pH: bitter metallic taste; corrosion. High pH: slippery feel; soda taste; deposits 

Silver (Secondary Drinking Water Standards)

• Monitoring Requirements/Comments: National Secondary Drinking Water Standards are non-enforceable guidelines regulating contaminants that may cause cosmetic effects or aesthetic effects in drinking water. The EPA recommends secondary standards but does not require systems to comply with secondary MCLs. States may establish or enforce standards that differ from these recommendations.
• Secondary MCL (mg/L unless noted): 0.1
• Noticeable Effects Above Secondary MCL: Skin discoloration; graying of the white part of the eye

Sulfate (Secondary Drinking Water Standards)

• Monitoring Requirements/Comments: National Secondary Drinking Water Standards are non-enforceable guidelines regulating contaminants that may cause cosmetic effects or aesthetic effects in drinking water. The EPA recommends secondary standards but does not require systems to comply with secondary MCLs. States may establish or enforce standards that differ from these recommendations.
• Secondary MCL (mg/L unless noted): 250
• Noticeable Effects Above Secondary MCL: Salty taste

Total Dissolved Solids (Secondary Drinking Water Standards)

• Monitoring Requirements/Comments: National Secondary Drinking Water Standards are non-enforceable guidelines regulating contaminants that may cause cosmetic effects or aesthetic effects in drinking water. The EPA recommends secondary standards but does not require systems to comply with secondary MCLs. States may establish or enforce standards that differ from these recommendations.
• Secondary MCL (mg/L unless noted): 500
• Noticeable Effects Above Secondary MCL: Hardness; deposits; colored water; staining; salty taste

Zinc (Secondary Drinking Water Standards)

• Monitoring Requirements/Comments: National Secondary Drinking Water Standards are non-enforceable guidelines regulating contaminants that may cause cosmetic effects or aesthetic effects in drinking water. The EPA recommends secondary standards but does not require systems to comply with secondary MCLs. States may establish or enforce standards that differ from these recommendations.
• Secondary MCL (mg/L unless noted): 5
• Noticeable Effects Above Secondary MCL: Metallic taste