Sewer authority to replace aging Highway 1 force main under court consent decree; construction targeted for fall 2026

The Sewer Authority Mid‑Coastside (SAM) told the Mid Coast Community Council on April 8 that it will replace aging sections of the Highway 1 sewer force main under an accelerated schedule driven by a consent decree.

SAM representatives told the council the original ductile‑iron pipeline — portions of which have been in service for about 40 years — has experienced multiple failures and spills. SAM said the Environmental Research Foundation (ERF) consent decree requires replacement by June 30, 2027, and the agency awarded a design‑build contract in late 2024 to compress design and construction work into a single programmatic effort rather than spreading it over many years.

"We have had multiple failures and spills over past couple of years and that resulted in a consent decree ... which requires us to replace this pipeline by June 30th, 2027," SAM's presenter said. To meet that deadline, SAM opted for a progressive design‑build procurement so an engineering team and contractor can coordinate design, permitting and construction to shorten the schedule.

The project area runs from Vermont Avenue in Moss Beach south along Highway 1 to just south of Capistrano Road; SAM described roughly 6.5 miles of force mains and interceptors that feed the regional treatment plant. SAM said the work will replace ductile‑iron segments with high‑density polyethylene (HDPE) pipe and that trenchless bore crossings are planned for several highway crossings; an excavation at the Capistrano Road tie‑in is likely.

SAM circulated an initial study/mitigated negative declaration (IS/MND) for a 30‑day public review ending Feb. 27, 2026, and plans to take the final IS/MND to the SAM board for consideration April 27. The authority listed a set of permits still to obtain, including a coastal permit or exemption, state water board approvals, and incidental‑take authorization from Fish & Wildlife (SAM noted gopher snake and red‑legged frog concerns and said biologists will be part of mitigation and monitoring).

On cost, SAM said prior engineering estimates two years ago were roughly $10–12 million and that engineers now estimate about $13–14 million. The design‑build contractor will submit a guaranteed maximum price (GMP) to SAM in May or June; the SAM board will decide whether to accept the GMP or to complete 100% design and bid the work. SAM emphasized the GMP is not yet final.

Construction is targeted for a fall 2026 start, with an anticipated 12‑month construction duration. SAM said it is using a temporary staging area on Harbor District land to support potholing and verification work; that staging area will be taken down until full construction mobilization. SAM also said temporary bypass piping will maintain sewer service during replacement work and that the contractor will be responsible for road repairs and restoring pavement to its prior condition.

Council members and residents asked about traffic impacts, hours of work, cost escalation, the effect of two different lawsuits discussed in the meeting record, and whether the public was notified in time to comment on environmental documents. SAM said traffic impacts will be localized and primarily off the highway, that daytime work is expected with potential night work for constrained highway crossings, and that the GMP will be presented to the board this spring.

The authority offered to host plant tours for the council and public, and SAM staff encouraged residents to submit written comments on the IS/MND by the public deadline; SAM said comments received by April 17 could be addressed prior to the board meeting.

What happens next: SAM will present the final IS/MND to its board April 27 and expects the contractor to provide a GMP in May or June 2026. If the board accepts the GMP and permits come through, construction could begin in fall 2026 with work staged from temporary Harbor District property and overseen by biologists and environmental monitors.