California Water Service Co - Westlake, CA
Lead detected, under the action levels
Latest 90th-percentile lead: 3 ppb (monitoring period 2022-2024). The federal action level is 15 ppb today and drops to 10 ppb in Nov 2027; EPA's health goal is 0. Lead was measured in sampled homes but the 90th percentile is under both action levels. EPA's health goal for lead is zero, so test your own tap if your home was built before 1986 or anyone in it is pregnant or a young child.
Who runs the water here
California Water Service Co - Westlake serves about 19,544 people through 6,929 service connections, which makes it a large system under EPA's size classes. It is privately owned and draws surface water, in Ventura County, California. EPA system ID: CA5610016; phone on file: 408-367-8593. Ask them for your address in their service line inventory - every system had to publish one by Oct 2024.
Every lead result on file
That is up 3 ppb from 0 ppb in the period ending 2021. The highest 90th-percentile result EPA holds for California Water Service Co - Westlake is 7.4 ppb across 3 monitoring periods, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2024 | 3 ppb |
| 2021 | 0 (not detected) |
| 2018 | 7.4 ppb |
Against other California systems
Of the 2,884 California systems with a lead result, the median latest reading is 0 ppb; 30 are over 15 ppb right now and 215 have gone over at some point. California Water Service Co - Westlake's 3 ppb sits at the 86th percentile in California and the 83rd nationally (higher means more lead).
Nearby utilities
67 other systems share Ventura County; 3 of them have a higher latest lead result than California Water Service Co - Westlake. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Oxnard Water Dept | 200,232 | 0 (not detected) |
| Ventura Water Department | 112,285 | 0 (not detected) |
| Ventura Wwd No. 8 - Simi Valley | 94,736 | 0 (not detected) |
| Cal American Water Co | 66,809 | 3 ppb |
| City Of Thousand Oaks Water Department | 54,770 | 0 (not detected) |
| Camarillo Water Dept | 47,701 | 0 (not detected) |
| Golden State Water Company - Simi Valley | 45,086 | 6 ppb |
| Ventura Cwwd No. 1 - Moorpark | 35,514 | 0 (not detected) |
| Camrosa Water District | 32,700 | 0 (not detected) |
| City Of Santa Paula | 31,786 | 0 (not detected) |
What to do in your house
Test your own tap with a certified lab first-draw sample; San Jose, CA may offer free or low-cost kits through the utility. If your own line is lead, replacing the private side runs about $1,200-$12,300 (EPA average about $4,700). Ask California Water Service Co - Westlake whether it covers that cost before hiring anyone - many utilities now do.
These figures describe homes the utility sampled, not your tap. Only your service line record or a test of your own water answers the question for your house. What a 90th-percentile result does and does not tell you: how to read a lead result. Size matters more than most people expect: small vs large water systems.