Public Water Authority
Sonoma County Water Agency (Sonoma Water)
Serving Sonoma and Marin Counties through Sonoma Water’s wholesale transmission system and its eight primary retail water contractors
Population served
More than 600,000 residents in Sonoma and Marin Counties through wholesale domestic-water supply and delivery; active CWS PWS CA4910020 is listed by California Drinking Water Watch as Sonoma County Water Agency.
State system code
FIPS 06
Billing frequency
A dedicated this detail was not publicly posted. For household accounts. Sonoma Water adopts fiscal-year wholesale rates effective July 1, 2026 under the Restructured Agreement for Water Supply; the household billing frequency is set by the local retail contractor.
Provider briefing
How this utility’s billing works
Sonoma County Water Agency (Sonoma Water) operates as a public water authority serving Sonoma and Marin Counties through Sonoma Water’s wholesale transmission system and its eight primary retail water contractors. Customers should use the provider’s current account-specific bill and official customer-service instructions as the final authority for deadlines, balances, and service requests.
The published water-rate framework is described as Wholesale water-transmission rate structure based on aqueduct/contractor service, water-supply operations, infrastructure, debt service, and fixed meter or capacity charges. The FY2026–27 Board action states that rates must cover projected operation, maintenance, infrastructure, and debt-service requirements. The published wholesale rate is passed through in varying ways by the eight retail contractors and is not a residential tier schedule.. Bills are generated a dedicated this detail was not publicly posted. for household accounts. sonoma water adopts fiscal-year wholesale rates effective july 1, 2026 under the restructured agreement for water supply; the household billing frequency is set by the local retail contractor., and a typical residential cost reference is A dedicated this detail was not publicly posted. At Sonoma Water’s wholesale level. The Agency reported that its FY2025–26 wholesale adjustment was expected to translate to roughly $0–$3 per month for many households if fully passed through, but the total retail bill depends on the contractor’s meter charge, usage tiers, sewer, stormwater, conservation programs, and local fees. Residents must use the local retailer’s current 2026 bill calculator.. These descriptions are useful planning benchmarks; actual charges can change with meter size, usage, sewer averaging, local taxes, drought stages, or account-specific fees.
Wastewater and sewer calculation
A dedicated this detail was not publicly posted. For a countywide household formula. Sonoma Water performs localized wastewater collection, treatment, and reuse in selected facilities serving more than 22,000 residences and businesses, but it does not establish one residential sewer calculation for all wholesale drinking-water customers. Retail water and sewer agencies set their own winter-average, flat-rate, or usage-based formulas.
Meter and infrastructure notes
A dedicated this detail was not publicly posted. For household meter reading. Sonoma Water measures wholesale transmission deliveries and system operations, while local retail contractors read residential meters and issue bills on their own monthly, bi-monthly, or other schedules. The Agency’s regional flow and supply records should not be presented as the customer’s retail meter technology.
Emergency water support
Report a leak or water emergency
Sonoma Water’s public agency contact is (707) 526-5370 for regional water-supply, transmission, and agency matters. A resident should report a household leak, main break, pressure emergency, or water-quality concern to the retail provider serving the service address; no countywide Sonoma Water retail emergency IVR is published.
Official starting point
Choose the right next step
Reading this profile
A practical reference for Sonoma and Marin Counties through Sonoma Water’s wholesale transmission system and its eight primary retail water contractors
Sonoma County Water Agency (Sonoma Water) is listed here as a public water authority. The profile separates account actions—such as paying a bill or requesting service—from explanatory material about rates, meters, wastewater, leaks, and delinquency.
Because utility rules can vary by account class, meter size, service address, billing date, and local ordinance, treat the published bill and current provider website as the final authority. Use this profile to locate the correct channel and prepare better questions for customer service.
If your issue is urgent, start with the provider’s emergency number or official payment route rather than waiting for an email response. Keep a written record of calls, confirmation numbers, notice dates, and documents you submit.