County · California
Lake County, California: drinking water records
This overview covers 14 ZIP codes and 44 community water systems in Lake County. It also stands in for 1 ZIP codes whose utility has too little EPA data for a page of its own.
System population figures are summed from EPA registry records and can overlap where wholesalers and retail systems serve the same people. They are not a Census county-population estimate.
Water systems with the most complete records
| Water system | People served | PFAS survey results | PFAS found | Health-based violations | Lead, 9 in 10 homes at or below |
|---|---|---|---|---|---|
| Highlands Mutual Water Company CA1710003 | 7,772 | 120 | 0 | 4 | 4.6 ppb |
| Mt. Konocti Mutual Water Company CA1710014 | 4,360 | 120 | 0 | 3 | 0 ppb |
| Hidden Valley Lake CSD CA1710015 | 6,235 | 60 | 0 | 0 | 0 ppb |
| Konocti County Water District CA1710006 | 5,928 | 120 | 2 | 0 | 0 ppb |
| Lakeport, City of CA1710004 | 4,762 | 180 | 0 | 0 | 0 ppb |
| Golden State Water Co.-Clearlake System CA1710002 | 4,644 | 120 | 0 | 0 | 0 ppb |
| Kelseyville Co Waterworks District 3 CA1710007 | 4,102 | 240 | 0 | 0 | 5.2 ppb |
| Cobb Area County Water District CA1710012 | 3,515 | 0 | 0 | 1 | 0 ppb |
| Clearlake Oaks County Water District CA1710001 | 2,359 | 0 | 0 | 2 | 0 ppb |
| Lucerne Water Co. - Cal Water Service CA1710005 | 2,129 | 120 | 0 | 0 | 0 ppb |
| Callayomi County Water District CA1710013 | 1,598 | 0 | 0 | 1 | 0 ppb |
| Lower Lake County Water District CA1710010 | 1,326 | 0 | 0 | 1 | 0 ppb |
| Loch Lomond Mutual Water Co CA1700518 | 693 | 0 | 0 | 1 | 5.8 ppb |
| Bella Lago Mobile Home Park CA1700610 | 152 | 0 | 0 | 1 | 0 ppb |
| Pier 1900 Homeowner'S Association CA1700630 | 152 | 0 | 0 | 1 | 0 ppb |
| Blue Lakes Improvement Club CA1700561 | 90 | 0 | 0 | 1 | 0 ppb |
| Lazy S Mobile Ranch CA1700609 | 73 | 0 | 0 | 15 | 4.6 ppb |
| Twin Creeks Mobile and RV Village CA1700580 | 50 | 0 | 0 | 1 | 3.6 ppb |
| Blue Lakes Mobile Home Park CA1700589 | 32 | 0 | 0 | 1 | 0 ppb |
| Golden State Water Company - South Shore CA1700519 | 30 | 0 | 0 | 21 | 2.8 ppb |
| Lake County Csa 21 - North Lakeport CA1710021 | 4,046 | 0 | 0 | 0 | 0 ppb |
| Nice Mutual Water Company CA1710008 | 2,929 | 0 | 0 | 0 | 0 ppb |
| Lake County Csa 20 - Soda Bay CA1710022 | 2,003 | 0 | 0 | 0 | 0 ppb |
| Lake County Csa 2 - Spring Valley CA1710018 | 1,531 | 0 | 0 | 0 | 0 ppb |
| Buckingham Park Water District CA1710011 | 1,521 | 0 | 0 | 0 | 0 ppb |
ZIP reports in Lake County
No ZIP report in this county is published yet.
These ZIP codes are covered by this overview because their utility has too little EPA data for a separate page: 95493.
Sources and scope
EPA UCMR 5 occurrence data, samples collected 2023-01-03 – 2026-06-17, final release, August 2026 (file dated Aug 28, 2026); EPA SDWIS via ECHO, 2026Q2 extract (file dated Jul 9, 2026); EPA service-area boundaries v3.0; Census 2020 ZCTAs. Page generated 2026-09-03.
Counts cover the systems that report this county to EPA. A water system may cross county lines. "Found" means at least one result at or above the laboratory reporting level; it is not a compliance finding.