Tapcensus

Water quality in Thousand Oaks, California

Thousand Oaks is in Ventura County. 95 active public water systems serve the county; 37 had an EPA violation in the past three years.

Most likely your provider

California Water Service CO Westlake CA5610016 · Community water system · Surface water purchased
Serves 19,544 people Rules violated, past 3 years 0 Last sanitary survey Nov 15, 2024 Distance 3.6 mi

Your location is within the outer bounds of this system's EPA service area.

Other community water systems in Ventura County

67 systems, nearest first
SystemServesStatusRules violated, 3 yrDistance
City of Thousand Oaks Water Department
54,770 0 1.5 mi
Cal American Water CO
66,809 0 3.3 mi
Calleguas Municipal Water Dist
0 0 3.6 mi
Ventura Cwwd No. 38 Lake Sherwood
1,759 0 4.1 mi
Camrosa Water District
32,700 0 4.7 mi
Triunfo Water & Sanitation District
13,898 0 6.1 mi
Ventura Cwwd No. 1 Moorpark
35,514 0 7.6 mi
Ventura Wwd No. 8 Simi Valley
94,736 0 9.0 mi
Golden State Water Company Simi Valley
45,086 0 9.2 mi
Ventura Cwwd No. 19 Somis
1,429 0 9.3 mi
Waters Road Domestic Users Group
25 0 9.8 mi
Camarillo Water Dept
47,701 0 10.4 mi
Brandeis Bardin Institute
665 2 10.7 mi
Ventura Cwwd No. 17 Bell Canyon
1,946 0 10.8 mi
Solano Verde Mutual Water CO
100 0 10.8 mi
Cal American Yerba Buena
690 0 10.8 mi
Del Norte Mutual Water Co.
215 3 11.2 mi
Pleasant Valley Mutual Water CO
5,306 1 11.3 mi
Cal American WC las Posas Estates
2,043 0 11.6 mi
Crestview Mutual Water CO
2,079 0 11.9 mi
United Wtr Cons Dist
0 0 12.2 mi
Elkins Ranch
150 2 12.5 mi
South Mountain Mutual Water CO
58 0 13.6 mi
Navalair Mobile Home Park
160 1 13.7 mi
Esterina Properties
50 1 14.3 mi
All 68 community water systems in Ventura County
Non-community systems in Ventura County (27: schools, campgrounds, workplaces, restaurants)

These systems serve places you visit rather than homes.

SystemServesStatusRules violated, 3 yrUnresolved
Ventura Farms
100 0 0
Foxfield Riding School
120 0 0
The Ranch at Live Oak
82 1 1
Glass House Camarillo Cultivation, LLC
450 0 0
Laguna Vista School/oceanview School Dis
377 0 0
Oxnard Pallet Company
38 1 0
GP Anacapa Foods, Llc.
50 0 0
Bouquet Multimedia
100 0 0
Nishi Quality Flowers, Inc.
92 1 1
Santa Clara School
39 0 0
State Ready Mix, Inc.
Ventura
25 1 1
Rio Mesa High School/oxnard Uhs
2,600 1 1
Vulcan Materials Company Cal Mat
30 1 1
Rio School Dist/rio del Valle School
820 0 0
Rio School Dist/ Rio Real School
550 0 0
Beedy Water Company, LLC
35 0 0
Vineyard Mutual Water Company/industrial
259 0 0
Thomas Aquinas College
382 1 0
Pyramid Flowers
30 1 0
Lake Piru Park Uwcd
960 0 0
Dennison Park
102 1 0
Usfs Wheeler Gorge Campground
500 0 0
Smith Forks Water System
3,000 1 0
Camp Scheideck
33 1 1
Usfs Chuchupate Ranger Station
26 1 1
Channel Islands National Park
30 0 0
Santa Clara Resources
30 1 0
About this data

Water systems are matched to Ventura County, nearest to Thousand Oaks first. Your exact provider depends on your address and connection; the largest community water system in a county is usually the city or town utility. Distances are measured to the centre of the service area EPA publishes for the system.

Town locations and ZIP code areas come from U.S. Census Bureau 2020 files.

Source: the U.S. EPA's Enforcement and Compliance History Online system (ECHO), which publishes the federal Safe Drinking Water Information System. EPA's terms and values are shown as published. The California records are from EPA's data refresh of Oct 7, 2026; EPA refreshes this data quarterly, and states report to EPA with a lag of three to six months, so the newest violations may not appear yet. Retrieved from ECHO on Oct 11, 2026.