Public water system · CA5610016
ActiveCalifornia Water Service Co - Westlake
At a glance
California Water Service Co - Westlake (PWSID CA5610016) is an active community water system in Ventura County, California. It reports serving 19,533 people through 6,931 service connections. Its primary water source is purchased surface water, and EPA lists it as privately owned. EPA's Safe Drinking Water Act records list no violations for this system.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
19,533
Service connections
6,931
Primary source
SWP
Purchased surface water
System type
CWS
Community water system
System record
How does California Water Service Co - Westlake compare with other water systems in Ventura County?
By EPA's size categories, California Water Service Co - Westlake is a large system (10,001 to 100,000 people). Ventura County has 95 active public water systems. Its population served is about twice the county average of 9,293 people per system, and accounts for 2.2% of the 882,799 people reported by systems filed under the county. Across California, the 7,479 active systems average 5,706 people each. Nationally, the average active community water system reports serving 6,703 people, so California Water Service Co - Westlake is about 191% above that figure.
What does “community water system” mean?
A community water system serves at least 15 connections used by year-round residents, or regularly serves at least 25 year-round residents. Homes, apartments and mobile-home parks are served by these. California has 2,997 active community water systems, 40% of the state's 7,479 active systems. Purchased surface water means the system buys surface water from another public water system rather than drawing its own. 506 California systems (6.8%) list purchased surface water as their primary source.
Who owns and regulates California Water Service Co - Westlake?
EPA lists California Water Service Co - Westlake as privately owned. The CA state drinking water program is its primacy agency, the regulator with primary enforcement responsibility for the system under the Safe Drinking Water Act. 59 of the 95 active systems in Ventura County (62%) are also privately owned.
Does California Water Service Co - Westlake have drinking water violations?
No SDWA violations on record.
EPA's SDWA violation and enforcement data (via EPA ECHO, updated quarterly) lists no violations for California Water Service Co - Westlake. For the latest compliance status, check EPA ECHO for current compliance history.
California Water Service Co - Westlake: frequently asked questions
Who runs California Water Service Co - Westlake?
California Water Service Co - Westlake (PWSID CA5610016) is a community water system privately owned. It is regulated by the CA state drinking water program.
How many people does California Water Service Co - Westlake serve?
California Water Service Co - Westlake reports serving 19,533 people through 6,931 service connections in Ventura County, California.
Where does California Water Service Co - Westlake get its water?
EPA SDWIS lists this system's primary water source as purchased surface water. Purchased surface water means the system buys surface water from another public water system rather than drawing its own.
Does California Water Service Co - Westlake have any drinking water violations?
EPA's Safe Drinking Water Act records list no violations for this system.
Is California Water Service Co - Westlake's water safe to drink?
AquaCensus shows EPA compliance records, not current water test results, so it cannot say whether the water is safe at a given moment. EPA's Safe Drinking Water Act records list no violations for this system. For current results, consult the system's annual water quality report, EPA ECHO, or the CA state drinking water program.
Where can I find California Water Service Co - Westlake's water quality report?
As a community water system, California Water Service Co - Westlake must deliver an annual water quality report, called a Consumer Confidence Report, to its customers by July 1 each year, covering the previous calendar year. The system can provide a copy on request.
Other water systems in Ventura County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Oxnard Water Dept | Ventura | 200,232 | Community | Purchased surface water |
| Ventura Water Department | Ventura | 113,500 | Community | Surface water |
| Ventura Wwd No. 8 - Simi Valley | Ventura | 94,738 | Community | Purchased surface water |
| Cal American Water Co | Ventura | 66,809 | Community | Purchased surface water |
| City of Thousand Oaks Water Department | Ventura | 53,157 | Community | Purchased surface water |
| Camarillo Water Dept | Ventura | 46,824 | Community | Purchased surface water |
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About this data
Source: U.S. EPA Safe Drinking Water Information System (SDWIS) and SDWA violation records, via EPA ECHO, as published October 1, 2026 — AquaCensus refreshes it quarterly. See the methodology for how records are matched, cleaned and scored.
Cite as: AquaCensus, “California Water Service Co - Westlake, PWSID CA5610016, California”, https://aquacensus.com/water-systems/california/california-water-service-co-westlake-ca5610016 (data as of October 1, 2026).