Private Investor-Owned Utility
California Water Service Company - Los Altos Suburban System (CWSC Los Altos Suburban)
Serving Los Altos and portions of Cupertino, Los Altos Hills, Mountain View, and Sunnyvale in Santa Clara County
Population served
69,973 people; 17,170 residential service connections, 1,357 commercial connections, and 3 industrial connections according to California Drinking Water Watch for active system CA4310001.
State system code
FIPS 06
Billing frequency
Generally monthly billing, with the bill showing the service period, meter read dates, current charges, due date, and prior balance. The exact read and due-date calendar is premise-specific.
Provider briefing
How this utility’s billing works
California Water Service Company - Los Altos Suburban System (CWSC Los Altos Suburban) operates as a private investor-owned utility serving Los Altos and portions of Cupertino, Los Altos Hills, Mountain View, and Sunnyvale in Santa Clara County. 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 CPUC-regulated increasing-block metered residential structure for the Los Altos tariff area, with a fixed monthly service charge plus volumetric charges. The July 1, 2026 Residential Metered Service LAS tariff sets 1-6 CCF at $2.7706 per CCF, 7-20 CCF at $11.0514, 21-30 CCF at $13.8803, and over 30 CCF at $16.5836, plus a $47.56 monthly charge for a 5/8 x 3/4-inch meter; one CCF is approximately 748 gallons. Applicable CPUC fees, surcharges, surcredits, and CAP schedules may also apply.. Bills are generated generally monthly billing, with the bill showing the service period, meter read dates, current charges, due date, and prior balance. the exact read and due-date calendar is premise-specific., and a typical residential cost reference is Approximately $71.74 for 5,000 gallons and $101.29 for 7,000 gallons on a 5/8 x 3/4-inch meter using the July 1, 2026 LAS residential tariff and 1 CCF approximately equal to 748 gallons. These estimates include the fixed service charge and volumetric water charge but exclude sewer, taxes, CPUC fees, surcharges, surcredits, and any nonstandard meter charges.. 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
Cal Water bills the Los Altos Suburban potable-water charge. Sewer or wastewater charges are normally imposed separately by the applicable Santa Clara County or municipal sewer agency and are not governed by the Cal Water LAS tariff. The sewer agency may use actual water consumption, a winter average, a residential cap, or a fixed equivalent-unit charge. Customers should compare the water meter usage with the separate sewer bill and ask the serving agency for its current base, usage, winter-average, and adjustment rules.
Meter and infrastructure notes
The Los Altos Suburban system uses customer water meters and Cal Water's periodic billing reads. Cal Water's 2026 infrastructure plan identifies implementation of advanced metering infrastructure as a future upgrade, but the district page does not establish that every account already has AMI or publish a fixed local route day. Customers should use the bill's read dates and current/previous reads, review usage history in the portal, and ask Cal Water to confirm the exact meter technology and leak-alert capability for the premise. The district reports 297 miles of pipeline, 65 booster pumps, 46 storage tanks, imported treated surface water from Santa Clara Valley Water District, and local groundwater.
Emergency water support
Report a leak or water emergency
For water emergencies, main breaks, service-line leaks, flooding, or suspected water-quality problems in the Los Altos Suburban District, call 650-917-0152; Cal Water lists the same number for main and after-hours contact. Call 911 for an immediate life-safety emergency and avoid contact with contaminated or electrically hazardous water.
Official starting point
Choose the right next step
Reading this profile
A practical reference for Los Altos and portions of Cupertino, Los Altos Hills, Mountain View, and Sunnyvale in Santa Clara County
California Water Service Company - Los Altos Suburban System (CWSC Los Altos Suburban) is listed here as a private investor-owned utility. 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.