Lake County, California — public water systems
At a glance
81 active public water systems are filed under Lake County, California in EPA's SDWIS records, together reporting 72,454 people served. The largest is Highlands Mutual Water Company, which reports serving 7,772 people. 43 are community water systems serving people where they live; the other 38 are non-community systems, such as schools, workplaces, campgrounds and gas stations with their own supply.
Dataset updated . Source: EPA SDWIS/ECHO, refreshed quarterly.
Active systems
81
Population served
72.5K
Community systems
43
Groundwater share
74.1%
How does Lake County compare with other California counties?
Lake County has the 35th-most active public water systems among the 201 counties listed for active California systems in EPA records; among the 72 with 3 or more systems, the median has 73. Its systems report 72,454 people served in total, the 42nd-largest county figure in the state and 0.2% of the statewide total. The average system here reports serving 895 people, well below the California average of 5,706. Population figures are what each system reports; people served by more than one system, such as a wholesaler and the town that buys from it, are counted by each.
Where does Lake County's drinking water come from?
By primary water source, Lake County's active systems draw on groundwater (58, 72%), surface water (21, 26%), groundwater under influence of surface water (1, 1.2%) and purchased groundwater (1, 1.2%). Overall, 74% rely mainly on groundwater (including purchased groundwater) and 26% on surface water, compared with 85% and 15% across California. Groundwater means the system draws its water from wells or springs fed by underground aquifers. The county's largest system, Highlands Mutual Water Company, draws primarily on surface water.
What kinds of water systems operate in Lake County?
Lake County's active systems break down as 43 community systems (53%), 2 non-transient non-community systems (2.5%) and 36 transient non-community systems (44%). 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. A non-transient non-community water system regularly serves at least 25 of the same people for more than six months a year, but not where they live. Schools, factories, office buildings and hospitals with their own supply are typical examples. A transient non-community water system serves places where people do not stay long, such as gas stations and campgrounds, and regularly serves at least 25 people a day for at least 60 days a year. EPA lists their owner types as private (74%), local government (21%), federal government (3.7%) and state government (1.2%).
The 50 largest water systems in Lake County
🔒 Create a free account to export CSV| # | Water system | County | Population served | Type | Source |
|---|---|---|---|---|---|
| 1 | Highlands Mutual Water Company | Lake | 7,772 | Community | Surface water |
| 2 | Hidden Valley Lake Csd | Lake | 6,235 | Community | Groundwater |
| 3 | Konocti County Water District | Lake | 5,928 | Community | Surface water |
| 4 | Lakeport, City of | Lake | 4,762 | Community | Surface water |
| 5 | Golden State Water Co.-Clearlake System | Lake | 4,644 | Community | Surface water |
| 6 | Mt. Konocti Mutual Water Company | Lake | 4,360 | Community | Surface water |
| 7 | Kelseyville Co Waterworks District 3 | Lake | 4,102 | Community | Groundwater |
| 8 | Lake County Csa 21 - North Lakeport | Lake | 4,046 | Community | Surface water |
| 9 | Cobb Area County Water District | Lake | 3,515 | Community | Groundwater |
| 10 | Nice Mutual Water Company | Lake | 2,929 | Community | Surface water |
| 11 | Clearlake Oaks County Water District | Lake | 2,359 | Community | Surface water |
| 12 | Lucerne Water Co. - Cal Water Service | Lake | 2,129 | Community | Surface water |
| 13 | Lake County Csa 20 - Soda Bay | Lake | 2,003 | Community | Surface water |
| 14 | Callayomi County Water District | Lake | 1,598 | Community | Groundwater |
| 15 | Lake County Csa 2 - Spring Valley | Lake | 1,531 | Community | Surface water |
| 16 | Buckingham Park Water District | Lake | 1,521 | Community | Surface water |
| 17 | Lower Lake County Water District | Lake | 1,326 | Community | Groundwater |
| 18 | Lakeside County Park | Lake | 1,000 | Transient non-community | Groundwater |
| 19 | Upper Lake County Water District | Lake | 989 | Community | Groundwater |
| 20 | Rotten Robbie | Lake | 899 | Transient non-community | Groundwater |
| 21 | Loch Lomond Mutual Water Co | Lake | 693 | Community | Groundwater |
| 22 | Harbor View Mutual Water Company | Lake | 550 | Community | Surface water |
| 23 | Lake County Csa 13 - Kono Tayee | Lake | 449 | Community | Groundwater |
| 24 | Harbin Hot Springs | Lake | 401 | Non-transient non-community | Groundwater under influence of surface water |
| 25 | Lakeport Cinemas | Lake | 400 | Transient non-community | Groundwater |
| 26 | Anderson Springs Csd | Lake | 373 | Community | Groundwater |
| 27 | Huttopia Six Sigma Campground | Lake | 370 | Transient non-community | Groundwater |
| 28 | Cache Creek Vineyards | Lake | 310 | Transient non-community | Groundwater |
| 29 | Glenhaven Mutual Water Company | Lake | 300 | Community | Groundwater |
| 30 | Konocti Shores | Lake | 277 | Community | Groundwater |
| 31 | Cal 20 Village and Meadow Pointe Park | Lake | 255 | Community | Groundwater |
| 32 | Clear Water Mutual Water Company | Lake | 252 | Community | Surface water |
| 33 | Le Trianon Resort | Lake | 243 | Transient non-community | Groundwater |
| 34 | Mandala Water System | Lake | 212 | Transient non-community | Groundwater |
| 35 | Westgate Petroleum | Lake | 210 | Transient non-community | Groundwater |
| 36 | Saratoga Springs Retreat Center | Lake | 208 | Transient non-community | Groundwater |
| 37 | Walnut Cove Mobile Estates | Lake | 200 | Community | Groundwater |
| 38 | Reel in Resort | Lake | 200 | Transient non-community | Groundwater |
| 39 | Jitter Bean Coffee | Lake | 160 | Transient non-community | Groundwater |
| 40 | Konocti Harbor Resort | Lake | 155 | Transient non-community | Surface water |
| 41 | Bella Lago Mobile Home Park | Lake | 152 | Community | Groundwater |
| 42 | Pier 1900 Homeowner'S Association | Lake | 152 | Community | Groundwater |
| 43 | Lake Pillsbury Resort & Marina Inc. | Lake | 150 | Transient non-community | Surface water |
| 44 | Corinthian Bay Mutual Water Company | Lake | 150 | Community | Groundwater |
| 45 | Larsen'S Office Complex | Lake | 112 | Transient non-community | Groundwater |
| 46 | Usfs-Sunset Point Campground | Lake | 110 | Transient non-community | Groundwater |
| 47 | Thomas Water System | Lake | 110 | Transient non-community | Groundwater |
| 48 | Lodge at Blue Lakes | Lake | 100 | Transient non-community | Groundwater |
| 49 | Cdf-Konocti Conservation Camp No. 27 | Lake | 100 | Community | Groundwater |
| 50 | Blue Lakes Improvement Club | Lake | 90 | Community | Groundwater |
All other water systems in Lake County (31)
The remaining active systems filed under Lake County, largest first, with the population each reports serving.
- Sunrise Shore Mutual Water Company83
- Northern California Vipassana Center80
- Indian Beach Resort75
- Lazy S Mobile Ranch73
- Baycliff Water70
- The Narrows Family Resort65
- Blue Lakes Village65
- Villa Blue Estates Water District60
- Innisfree Water Company56
- Brassfield Estate Winery54
- Lake Pillsbury Ranch Water Company53
- Wildwood50
- Twin Creeks Mobile and Rv Village50
- Mendo Mill and Lumber Company46
- Langtry Farms41
- Wall Water40
- Usfs-Middle Creek Cg40
- Richmond Park Resort34
- Blue Lakes Mobile Home Park32
- Golden State Water Company - South Shore30
- The Mercantile28
- Mountain of Attention Water26
- Sky Park Properties25
- Hidden Valley Food Mart25
- Windflower Point Mutual Water Company25
- Tonys Fresh Market Round Lake Beach25
- Three Brothers Travel Plaza25
- Usfs Oak Flat Water System25
- Pine Acres Blue Lake Resort25
- Jack in the Box - Lakeport, Ca25
- Jago Bay Mutual Water Company11
Lake County water systems: frequently asked questions
How many public water systems are in Lake County, California?
EPA's SDWIS records file 81 active public water systems under Lake County, California: 43 community systems (53%), 2 non-transient non-community systems (2.5%) and 36 transient non-community systems (44%).
Who supplies drinking water in Lake County, CA?
The largest community water systems filed under Lake County are Highlands Mutual Water Company (7,772 people served), Hidden Valley Lake Csd (6,235 people served) and Konocti County Water District (5,928 people served). Which system serves a particular address depends on its service area, which EPA's SDWIS records do not include; a water bill or the local utility can confirm it.
Does Lake County's drinking water come from groundwater or surface water?
Of the 81 active public water systems in Lake County, 74% draw mainly on groundwater and 26% on surface water, counting purchased supplies. The largest system, Highlands Mutual Water Company, uses surface water.
Where can I find a water quality report for Lake County?
Each community water system must deliver an annual water quality report, called a Consumer Confidence Report, to its customers by July 1, covering the previous calendar year. 43 community systems are filed under Lake County, so the report to look for is the one from the system that supplies your address.
How can I check violations for a water system in Lake County?
Open the system's profile from the list on this page. Each profile shows the most recent Safe Drinking Water Act violations in EPA's records, with plain-English labels and whether each one is resolved. For current compliance status, EPA ECHO is the primary source.
More California water systems
- All California public water systems· 7,479 active
- Butte County· 86 systems
- Contra Costa County· 84 systems
- Mono County· 84 systems
- Nevada County· 82 systems
- Imperial County· 76 systems
- Siskiyou County· 69 systems
- How to find out who supplies your drinking water
- How to find and read your annual water quality report
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, “Public water systems in Lake County, California”, https://aquacensus.com/water-systems/california/lake (data as of October 1, 2026).