County · California
Lake County, California: drinking water records
Explore EPA records for 44 community water systems across 14 ZIP codes in Lake County, then find water-testing resources and available recent monitoring-station readings.
Data as of EPA UCMR 5 final release, August 2026 (file dated Aug 28, 2026) · EPA SDWIS 2026Q2 (file dated Jul 9, 2026). How we build these pages
Drinking-water records
EPA survey and compliance records are historical reports. UCMR 5 results are available for 8 of the 44 listed systems in this snapshot. A system with no reported PFAS detection is not a test of every tap or every contaminant.
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 in this county
All 44 active community systems in the available county records, sorted by record completeness. Scroll the table to explore more systems.
| 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 ppbbelow the action level |
| Mt. Konocti Mutual Water Company CA1710014 | 4,360 | 120 | 0 | 3 | 0 ppbbelow the action level |
| Hidden Valley Lake CSD CA1710015 | 6,235 | 60 | 0 | 0 | 0 ppbbelow the action level |
| Konocti County Water District CA1710006 | 5,928 | 120 | 2 | 0 | 0 ppbbelow the action level |
| Lakeport, City of CA1710004 | 4,762 | 180 | 0 | 0 | 0 ppbbelow the action level |
| Golden State Water Co.-Clearlake System CA1710002 | 4,644 | 120 | 0 | 0 | 0 ppbbelow the action level |
| Kelseyville Co Waterworks District 3 CA1710007 | 4,102 | 240 | 0 | 0 | 5.2 ppbbelow the action level |
| Cobb Area County Water District CA1710012 | 3,515 | 0 | 0 | 1 | 0 ppbbelow the action level |
| Clearlake Oaks County Water District CA1710001 | 2,359 | 0 | 0 | 2 | 0 ppbbelow the action level |
| Lucerne Water Co. - Cal Water Service CA1710005 | 2,129 | 120 | 0 | 0 | 0 ppbbelow the action level |
| Callayomi County Water District CA1710013 | 1,598 | 0 | 0 | 1 | 0 ppbbelow the action level |
| Lower Lake County Water District CA1710010 | 1,326 | 0 | 0 | 1 | 0 ppbbelow the action level |
| Loch Lomond Mutual Water Co CA1700518 | 693 | 0 | 0 | 1 | 5.8 ppbbelow the action level |
| Bella Lago Mobile Home Park CA1700610 | 152 | 0 | 0 | 1 | 0 ppbbelow the action level |
| Pier 1900 Homeowner'S Association CA1700630 | 152 | 0 | 0 | 1 | 0 ppbbelow the action level |
| Westwind Mobile Home Park CA1700584 | 104 | 0 | 0 | 1 | 0 ppbbelow the action level |
| Blue Lakes Improvement Club CA1700561 | 90 | 0 | 0 | 1 | 0 ppbbelow the action level |
| Lazy S Mobile Ranch CA1700609 | 73 | 0 | 0 | 15 | 4.6 ppbbelow the action level |
| Twin Creeks Mobile and RV Village CA1700580 | 50 | 0 | 0 | 1 | 3.6 ppbbelow the action level |
| Blue Lakes Mobile Home Park CA1700589 | 32 | 0 | 0 | 1 | 0 ppbbelow the action level |
| Golden State Water Company - South Shore CA1700519 | 30 | 0 | 0 | 21 | 2.8 ppbbelow the action level |
| Lake County Csa 21 - North Lakeport CA1710021 | 4,046 | 0 | 0 | 0 | 0 ppbbelow the action level |
| Nice Mutual Water Company CA1710008 | 2,929 | 0 | 0 | 0 | 0 ppbbelow the action level |
| Lake County Csa 20 - Soda Bay CA1710022 | 2,003 | 0 | 0 | 0 | 0 ppbbelow the action level |
| Lake County Csa 2 - Spring Valley CA1710018 | 1,531 | 0 | 0 | 0 | 0 ppbbelow the action level |
| Buckingham Park Water District CA1710011 | 1,521 | 0 | 0 | 0 | 0 ppbbelow the action level |
| Upper Lake County Water District CA1710009 | 989 | 0 | 0 | 0 | 0 ppbbelow the action level |
| Harbor View Mutual Water Company CA1700568 | 550 | 0 | 0 | 0 | 0 ppbbelow the action level |
| Lake County Csa 13 - Kono Tayee CA1700554 | 449 | 0 | 0 | 0 | 0 ppbbelow the action level |
| Anderson Springs CSD CA1700502 | 373 | 0 | 0 | 0 | 2.7 ppbbelow the action level |
| Glenhaven Mutual Water Company CA1700508 | 300 | 0 | 0 | 0 | 6 ppbbelow the action level |
| Konocti Shores CA1700592 | 277 | 0 | 0 | 0 | 0 ppbbelow the action level |
| Cal 20 Village and Meadow Pointe Park CA1700595 | 255 | 0 | 0 | 0 | 0 ppbbelow the action level |
| Clear Water Mutual Water Company CA1700546 | 252 | 0 | 0 | 0 | 0 ppbbelow the action level |
| Walnut Cove Mobile Estates CA1700674 | 200 | 0 | 0 | 0 | 0 ppbbelow the action level |
| Corinthian Bay Mutual Water Company CA1700549 | 150 | 0 | 0 | 0 | 0 ppbbelow the action level |
| Cdf-Konocti Conservation Camp No. 27 CA1710800 | 100 | 0 | 0 | 0 | 0 ppbbelow the action level |
| Sunrise Shore Mutual Water Company CA1700536 | 83 | 0 | 0 | 0 | 8 ppbbelow the action level |
| Baycliff Water CA1700606 | 70 | 0 | 0 | 0 | 0 ppbbelow the action level |
| Blue Lakes Village CA1700596 | 65 | 0 | 0 | 0 | 0 ppbbelow the action level |
| Villa Blue Estates Water District CA1700579 | 60 | 0 | 0 | 0 | 10 ppbbelow the action level |
| Innisfree Water Company CA1700702 | 56 | 0 | 0 | 0 | 0 ppbbelow the action level |
| Mountain of Attention Water CA1700527 | 26 | 0 | 0 | 0 | 0 ppbbelow the action level |
| Windflower Point Mutual Water Company CA1700657 | 25 | 0 | 0 | 0 | 0 ppbbelow the action level |
USGS · Monitoring stations
The water, more recently.
Available station readings in Lake County, California. Each measurement keeps its time, unit and original source.
These readings describe water at a monitoring station. They do not test your tap, measure PFAS or lead, or determine whether water is safe to drink or swim in.
Recent observations load when this section comes into view.
How these readings update
We check for updates every 10 minutes while this section is visible and show supported observations from the last 48 hours. The time beside a reading is when USGS measured it; the checked time is when our service retrieved the response. We mark a reading more than 6 hours old as older. Provisional observations can change after USGS review. A missing reading does not mean zero or clean water.
Temperature, pH, dissolved oxygen, turbidity, conductivity, streamflow and water level are shown only where a station reports them. Different measurements have different units and sampling intervals. USGS data and documentation.
Your next step
Water testing, reports & local help.
Use these official directories to find your drinking-water agency, a certified laboratory and public water records. We have not yet added an individually reviewed local resource list for this county.
Official national directories
Water testing
Find your state’s private-well program
EPA’s state directory points well owners to local program information. Services and eligibility vary by state and county.
Water testing
Find a certified drinking-water laboratory
Use EPA’s directory to reach your state’s laboratory certification program. EPA does not provide on-request testing of residential drinking water.
Public records
Find your utility’s Consumer Confidence Report
EPA links to community water-system reports and explains how to read them. Look for your actual supplier rather than assuming every address in a county shares one system.
Public records
Explore USGS water observations
Find current and historical observations from USGS monitoring locations, including available stream, lake, and groundwater data. Measurements vary by station and do not replace a test of your household water.
A county overview cannot identify every property’s water provider. If you use a public water system, confirm its name on your bill and request its annual Consumer Confidence Report. Private wells need their own testing; public-system records do not describe a private well.
Understand water testing and laboratory reportsResource descriptions are compiled by Tap Water Lookup. Review dates describe our source check, not a new water sample. How we review sources · Suggest a correction
Explore your area
Local coverage in Lake County
14ZIP areas in this overview
Explore the water-system records, recent station readings and testing resources on this county page. They describe the systems and stations identified in each section; they are not a separate water test for every community.
Towns and communities
- Clearlake
- Clearlake Riviera
- Cobb
- Hidden Valley Lake
- Lower Lake
- Lucerne
- Nice
- North Lakeport
- Spring Valley
- Upper Lake
View ZIP areas and understand coverage
- 95422Clearlake
- 95423Spring Valley
- 95426Cobb
- 95435
- 95443
- 95451Clearlake Riviera
- 95453North Lakeport
- 95457Lower Lake
- 95458Lucerne
- 95461Hidden Valley Lake
- 95464Nice
- 95467Hidden Valley Lake
- 95485Upper Lake
- 95493
These Census ZIP Code Tabulation Areas are grouped here by their largest county overlap. A ZIP area can cross county lines and contain several water suppliers or private wells. Place labels reflect Census geography, not verified postal city names or utility service boundaries.
Records for these areas are currently presented in this county overview rather than individual ZIP reports. An unpublished report does not mean there are no water records. Confirm your supplier on your water bill; if you use a private well, testing your own well is the relevant next step.
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. Database prepared 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.
Compiled by Tap Water Lookup from the sources identified on this page. Read the methodology and review process.