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 upsizing sections from 8–15 inches up to 12–27 inches, a new 12‑inch diversion from Gable to Sykes, and a new 27‑inch alignment to improve the railroad crossing. He said some work in Highway 30 will require Oregon Department of Transportation approvals and substantial traffic control. Basin 5 improvements are mainly along Fourth Street and an undeveloped Fifth Street right‑of‑way and include upsizing 30‑inch piping to 36‑ and 42‑inch lines and a new 36‑inch alignment to abandon stacked tunnel piping that exacerbates surcharging.

City staff described community impacts and mitigation measures: open‑cut installation where feasible (with pavement and landscaping repairs), trenchless boring through rock where depths make open cut impractical, traffic control plans, and contractor requirements to maintain access and restore disturbed property. Staff identified two required easements in Basin 6 — on the Avamere property and at a Presbyterian Church — and said the city intends to acquire them before construction.

On costs and schedule, consultants said they would bid the work in the fall of 2025 and expected construction to start around January, with a typical construction window of about two years and completion by late 2027 or early 2028. The presentation showed baseline construction estimates by basin and added a 20% construction contingency plus an 8% escalation factor. After contingency and escalation, the consultants presented totals by basin (presented figures: Basin 4 roughly $16 million; Basin 6 roughly $8 million; Basin 5 roughly $4.8 million; overall program figures were presented by the consultants as just over $24 million for certain components).

On funding, city staff said design work was funded by a Community Development Block Grant (CDBG) of about $2.5 million that paid for environmental review and permitting. City staff said the Clean Water State Revolving Loan Fund (SRF) administered by the Oregon Department of Environmental Quality (DEQ) will be used for construction; Sharon said the project has been approved by DEQ and that SRF loans typically carry “very, low interest, generally between 1 to 3%.” Staff also discussed principal forgiveness eligibility and federal procurement requirements (Davis‑Bacon prevailing wage rules and Build America Buy America provisions) that would apply if SRF equivalency is used.

Councilors asked how the project would affect sewer rates and development charges. Councilor Hubbard asked, “How much is this gonna impact our sewer fees?” City staff responded that SRF loan repayments would be paid from user rates and that planned rate increases to cover debt service already had been incorporated into the city budget; staff also said the project would remove an additional surcharge now charged to new development in constrained basins — a surcharge that has been in effect since 2022 — if those basins are upsized.

Staff closed by noting the 90% plans and specifications had been submitted for internal review, permitting remains to be obtained (ODOT, railroad, DEQ and other environmental permits), and the city will continue utility coordination, easement acquisition, and public outreach. Crystal, the city communications lead, was named the public communications lead for the project and CONSORT’s public relations team will support outreach.

Next steps in the process are incorporation of staff comments into final design over the summer, concurrent permit applications and utility relocations, final bid documents in the fall, and easement acquisition prior to construction.