SVCSD Sewer Trunk Main Replacement Project

About the project

This multi-year project will replace approximately 1.8 miles of the existing 21-inch diameter sewer trunk main originally constructed in 1958 with a new 27-inch diameter main. The project is planned to be constructed in three phases, with the first phase beginning in the summer of 2019.

Project Update:

April 4, 2022

The Sonoma Valley County Sanitation District Sewer Trunk Main Replacement Project is making good progress. Construction will get underway in May of this year on Phase 4C. After this phase is completed, close to 30,000 linear feet of sewer trunk main will have been constructed since the first replacement project in 2003.

Planned 2022 Construction:

Phase 4C

The SVCSD Trunk Main Replacement Phase 4C project consists of the installation of 2,200 feet (0.4 miles) of 27-inch diameter sewer line along Happy Lane between Fairview and Orchard in Boyes Hot Springs

This project is the next phase of a sewer trunk main replacement project that has been ongoing since 2003.

Phase 4C will begin where the Agua Caliente Siphon Project ended in 2016 and will work its way north to Happy Lane.

How will this affect my neighborhood?

The project will not affect sewer service. If you live or have a business along the construction corridor, the construction may create short-term noise, and traffic delays.

Construction activities will incorporate measures to minimize and/or avoid potential noise and traffic impacts related to construction activities.

When is Project construction expected to start?

The next phase of the proposed project, Phase 4C, is expected to begin in May 2022 near the end of Buena Vida Court and will progress off-road towards the north onto Happy Lane where the project will be completed just north of Anthony Court. The project will impact some traffic patterns and residences along Happy Lane, Academy Lane, Buena Vida Drive, and Buena Vida Court.


Project work hours are Monday thru Friday 8AM to 6PM, excluding holidays.

Why is this project necessary?

The trunk sewer main to be replaced is approximately 60 years old and at the end of its life expectancy.

The project is being completed under a cease and desist order issued by the California Regional Water Quality Control Board to improve the sewer system’s ability to reliably handle dry and wet weather flows, and reduce sanitary sewer overflows (which occur during heavy rains and can result in wastewater entering local creeks).

Construction Completed:

Reach 4A: From the intersection of 6th Street West and Studley Street, continue north to Highway 12, continue north along State Highway 12, and continue west and north along Highway 12, ending in Ramon Street.

Reach 4B.1: Within Maxwell Farms Regional Park, is being advanced in coordination with Sonoma County Regional Parks to replace a portion of the existing sewer main that is under the baseball field. Improvements were planned as a part of the Maxwell Farms Regional Park Master Plan.

Reach 4B.2: Beginning at the intersection of Ramon Street and Highway 12 in Sonoma, crossing through Maxwell Farms Regional Park, and ending just north of Verano Avenue. This phase begins where Phase 4A ended in 2019 and worked its way north to tie into the Agua Caliente Siphon Project, which was constructed in 2016.

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For more information

For more information, contact: Andrea Rodriguez,