Fairfax Capacity and Creek Crossings Project (#957)

The Ross Valley Sanitary District is undertaking the Fairfax Capacity and Creek Crossings Project to upgrade and expand its sanitary sewer infrastructure in unincorporated Marin County and the Town of Fairfax. The project involves rehabilitating approximately 3,300 linear feet of aging 6-inch sanitary sewers using multiple trenchless and open-cut methods including pipe bursting, guided jack and bore, and aerial crossing, with new PVC or HDPE pipe installed to enhance system reliability and reduce inflow and infiltration. Additionally, the project will increase wet weather capacity by upsizing 400 feet of 15-inch gravity sewer to 18 inches and installing 2,000 feet of new 18-inch gravity main along Broadway and Merwin Avenue in downtown Fairfax. Private sewer laterals will be reconnected and repaired as needed to ensure full system integration. Four crossings of Fairfax Creek will be completed using trenchless techniques such as guided jack and bore and horizontal directional drilling, with two of these crossings occurring above ground to avoid excavation. Construction is scheduled to begin in June 2026 and conclude by November 2026, with work hours limited to 8 a.m. to 5 p.m. The project will disturb approximately 13,300 square feet across a 0.3-acre site, with all creek crossings designed to minimize environmental impact. The project’s primary objectives are to prevent sewer overflows during wet weather, replace outdated infrastructure, and improve long-term system capacity and resilience. All work will remain within existing alignments to reduce disruption. The Senior Engineer, Philip Benedetti, is the primary point of contact for the project, representing the Ross Valley Sanitary District, which is responsible for oversight and implementation in the 94901 zip code area of Fairfax, California.