California water systems, mapped
585 systems drawn on their service areas, coloured by the most recent water loss figure each one filed. Every shape is a link to that system's own filings.
- under 5.4%
- 5.4%–7.6%
- 7.6%–11.2%
- 11.2%–17.6%
- over 17.6%
- no figure filed
What a shape here is
The service areas come from the US EPA's national boundary layer, which the agency publishes as an estimate: it disclaims the spatial accuracy of the features and names local government as the accurate source. Some of those shapes were published by a state agency, a county or the utility itself, and some EPA modelled. In California, 2 of the 585 shapes drawn here are EPA models rather than published boundaries.
A boundary is not a customer list and not a legal service territory. Two systems can cover the same ground — a wholesaler and the retailer it supplies — and being inside one of these shapes does not make an address that system's ratepayer.
What is not on the map
24 California systems have filings on this site and no boundary in EPA's layer, so they are absent from the map and listed here instead:
- Amador Water Agency - Pg&e
- Big Bear Lake Department Of
- California - American Water Company - Los Angeles District - Bellflower
- California - American Water Company - Sacramento District - Security Park
- California American Water - San Diego District
- California American Water Company - Bishop
- California American Water Company - Ryan Ranch
- California American Water-sacramento District-suburban/rosemont
- Coachella Valley Water District Id11
- Lake Arrowhead Comm Svcs District 3610087
- Lompoc
- Lompoc
- Mid-peninsula Water District
- Norwalk
- Sacramento County Water Agency
- Sacramento County Water Agency - Metro Air Park
- Sacramento County Water Agency - Northgate 880
- Sonoma County Water Agency
- Thousand Oaks
- Thousand Oaks
- Tuolumne Utilites District - Cedar Ridge
- Tuolumne Utilites District - Phoenix Lake
- Tuolumne Utilites District - Scenic View
- Tuolumne Utilities District
Boundaries: US EPA Office of Research and Development, community water system service area boundaries,
retrieved 2026-09-09 and archived as data/archive/epa-cws-boundaries/2026-09-09-ca.geojson. The state outline behind them is a
US Census cartographic boundary file, drawn for orientation; no figure here is derived from it. Figures: California Department of Water Resources, as
filed by each utility — the California index carries them as a table, and
each system's page carries the archived cell every figure was read from.
Report a correction.