California Water Service - San Mateo System
San Mateo and vicinity, San Mateo County
Population reference
103,536 people; 22,823 residential, 2,630 commercial, and 8 industrial service connections reported for active PWS CA4110008
Billing detail
Broad public detail found
Official destination
Open provider website ↗Provider-specific findings
Billing and account research from public material
Provider-specific research notes are displayed separately from fields that contain only an unavailable-information marker. Read qualifiers in each note and verify current account terms with the provider.
- Billing frequency
- Monthly. The Bayshore district materials state that district services are metered, meters are read monthly, and customers are billed monthly based on metered water use. The issued statement controls the exact due date and service period.
- Rate structure
- Increasing-block conservation pricing for residential metered customers under CPUC Schedule BAR-1-R, Bay Area Region. Effective July 1, 2026, the 5/8 x 3/4-inch monthly readiness-to-serve charge is $34.47; usage is $4.2083 per CCF for 1–6 CCF, $16.8152 per CCF for 7–9 CCF, $21.0842 per CCF for 10–13 CCF, and $25.2184 per CCF above 13 CCF. One CCF is approximately 748 gallons. San Mateo residential bills can include the 1.350% San Mateo business-license surcharge, plus CPUC, Rate Support Fund, CAP, and other approved surcharges or surcredits.
- Residential cost reference
- Using the July 2026 BAR-1-R 5/8 x 3/4-inch schedule, a 5,000-gallon month is about 6.68 CCF and produces approximately $71.15 in basic water charges, or about $72.11 after the 1.350% San Mateo business-license surcharge, before other approved surcharges, surcredits, taxes, or separate sewer service. A 7,000-gallon month is about 9.36 CCF and produces approximately $117.76 in basic water charges, or about $119.35 after that surcharge. The exact bill depends on meter size, days in the billing period, usage, and line-item adjustments; this is a tariff calculation rather than a guaranteed average bill.
- Wastewater and sewer calculation
- The active CWS record and Cal Water Bayshore tariff cover potable water service. The reviewed Cal Water materials do not publish a San Mateo wastewater formula, winter-average method, or percentage tie-in. Sewer charges, if applicable, are billed or administered separately by the responsible local sewer agency or property arrangement; customers should use that agency's sewer account rules rather than infer wastewater charges from the Cal Water meter bill.
- Meter reading
- The San Mateo system is metered and the Bayshore district reads meters monthly. Cal Water's planning materials say it is piloting automatic meter reading and advanced metering infrastructure in several districts, but they do not state that AMR or AMI has been deployed to every San Mateo account. Customers should use the bill's read dates, meter number, and current/previous reads; the portal provides usage history, while Cal Water can confirm the exact meter technology and leak-alert capability for an individual premise.
- New-account deposit
- Cal Water Rule 6 allows a cash deposit or other approved credit security when an applicant does not establish credit, while Rule 7 governs deposit return. The exact deposit is account- and credit-specific rather than a universal San Mateo flat amount. After 12 consecutive months in which at least 10 bills were paid within 15 days after presentation and service was not discontinued for nonpayment, Cal Water automatically refunds the deposit as an account credit with applicable interest; a customer may also establish credit by another approved method and request return. A prior delinquency can require payment of the unpaid balance, reconnection charges, and a deposit to re-establish credit.
- Activation or transfer fee
- No single universal 2026 routine name-transfer fee is stated on the reviewed Bayshore district or payment pages. Cal Water's operating rules and tariffs separately govern new service, connections, meters, deposits, construction, inspections, and special facilities. A customer should obtain the premise-specific activation, connection, or deposit amount from Cal Water rather than assume that a routine account transfer has no possible charge.
Context, not a score
How documentation coverage compares
This profile
100%
overview fields with research notes
California
67%
records with any overview detail
National index
50%
records with any overview detail
Coverage measures what this directory documented. It does not measure service quality, affordability, or regulatory compliance.
Research record
Broad public detail found
7 of 7 fields in this section contain provider-specific public detail in dataset August 1, 2026.
Documented
100%
Primary verification routes
- California Water Service - San Mateo System public website ↗
Provider-controlled destination used to confirm current customer instructions.
- EPA SDWIS / ECHO lookup (CA4110008) ↗
Search the federal drinking-water database using public water system ID CA4110008.