Sonoma Water outlines $361 million five‑year CIP, highlights tank, well and resiliency projects

Sonoma Water Agency staff presented a summary of the water‑transmission capital program serving Sonoma and Marin counties and reviewed projects that affect the City of Sonoma’s wholesale water supply.

Kent Gilphy, Sonoma Water’s director of engineering, and the city’s public‑works leader summarized recent work to rehabilitate production wells, ongoing tank recoating, cathodic‑protection upgrades on transmission pipelines, booster station electrical and seismic upgrades, and planning for treatment modernization and aquifer storage and recovery pilots. The agency described a multi‑year tank rehabilitation program to recoat and add cathodic protection to storage tanks, and noted work on the Cattafi/Catati tanks and others that will be scheduled out over the next several years.

Major projects and program points included:

• Wells and drought resilience: Rehabilitation of multiple ground‑water wells (e.g., Todd Road, Occidental Road and Sebastopol Road wells), secured drought‑resiliency grant funds and evaluation of aquifer storage and recovery (ASR) pilot testing where feasible.

• Tank rehabilitation program: A 10‑year program (roughly $80 million) to recoat about 18 storage tanks and upgrade cathodic protection systems; recent completions included a 12‑million‑gallon tank return to service and a 6‑million‑gallon tank; larger tanks will be taken out of service one at a time for recoating and seismic foundation work.

• Cathodic protection and pipeline maintenance: Replacing passive corrosion protection on older aqueduct pipe with impressed current systems and rectifiers; work staged to address right‑of‑way and permitting constraints.

• Booster stations and electrical resiliency: Upgrades at several pump stations include seismic retrofits, redundant pump sets and flood‑protected electrical gear; procurement delays for specialty electrical equipment have affected some schedules.

• Treatment modernization and water rights: A multi‑phase project to move from chlorination systems that rely on gaseous chlorine to sodium hypochlorite, and to update treatment and corrosion control facilities; staff noted recent state guidance on water‑right approaches for planned aquifer recharge activities.

• Planning and resiliency: A comprehensive water‑transmission master plan is under development to prioritize projects beyond the five‑year horizon; a regional seismic‑resiliency study completed geotechnical work and identified hazard‑vulnerable locations.

Sonoma Water staff said the agency intends to present budget and rate information to water contractors in coming weeks and expects to return to contractor boards and councils with proposed rates in the March timeframe. The agency noted that some capital work has been deferred in the past but that critical projects are now coming due and that funding will remain a challenge.

City and public questions: Council members asked about where tank washout water is discharged during maintenance, the share of CIP funding covered by federal/FEMA grants (agency said a minority), and whether the agency’s proactive planning has meaningfully reduced risk; Sonoma Water staff said it has improved resilience but that deferred investments remain and that rates and grant resources will drive priorities.

What this means for Sonoma: Several projects have direct or indirect impacts on the city’s wholesale water supply, including the Sonoma booster station, the Sonoma 1 tank recoating schedule and other upgrades. Projects will be scheduled to limit outage impacts and will require environmental reviews and coordination before construction.

The agency encouraged interested elected officials and staff to request facility tours to see operations and infrastructure.