Proactive Condition Assessment to Evaluate the Remaining Service Life of a Critical Force Main

The India Street combined sewer force main is a critical part of the Portland Water District’s (PWD) infrastructure that conveys wastewater from the India Street Pump Station in downtown Portland to the East End Wastewater Treatment Facility. This 1.3-mile pipeline, made of 33-inch prestressed concrete cylinder pipe, was built in 1976. Like many wastewater force mains, it is a single asset with no redundancy. This assessment was intended to identify any potential issues that would impact its ability to reliably convey wastewater to the treatment plant.

PWD partnered with INSIGHT Water Technologies and HDR to conduct a comprehensive assessment in August 2025. The project used cutting-edge technology, including XK1 — a free-swimming, near-field electromagnetic inspection tool — which travels through the pipe using water flow and collects data continuously along its length. At the end of the pipeline, the device is collected, and the data is extracted and analyzed. Our team also performed a hydraulic assessment to evaluate the pipeline for transients and potential restrictions.

This state-of-the-art inspection, advanced field services and engineering analysis will help the PWD understand the pipe’s current health and identify any necessary actions to improve its long-term reliability.

While the data is still under final review, initial results show that the force main remains in good condition, with the ability to provide reliable service without short-term intervention. While PWD has engaged with similar approaches on the water side of the utility for nearly a decade, this is the first effort on wastewater infrastructure. PWD is engaged in a project to review water mains and wastewater force mains to develop a long-term plan to maintain reliable services for the coming decades.