St. Helens outlines multi‑basin wastewater upgrade to reduce overflows and support growth

City staff and consultants presented a wastewater capacity improvement project to the St. Helens City Council at a public forum on May 21, 2025, describing planned upsizing and realignments in three sewer basins to reduce sanitary sewer overflows and to enable future development in the city.

Mohammed, city staff, opened the presentation, saying the purpose was “to talk to you a little bit about the wastewater capacity improvement project.” CONSORT representatives then reviewed the alignments, construction methods and anticipated community impacts.

The project covers three basins. CONSORT engineer Brad described Basin 4 as “about a mile of piping” that will convert many existing 10‑ and 12‑inch pipes to 12‑ and 15‑inch pipes and add 21‑ and 24‑inch diversion piping to move flow away from Basin 5. He said the Basin 4 work follows alignments from the wastewater treatment plant through Plymouth, Ninth and Tualatin streets and through existing easements between Thirteenth and Fifteenth streets; some sections will require trenchless boring because pipes are 15–30 feet deep and the local geology is basalt.

Brad said Basin 6 involves roughly two miles of pipe work, including…