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Counties → California

Lake County, California

SDWIS compliance plate

Sheet CA033 · Lake County 81 sys · 1,460 viol · #719/3254

VIOL-SEVERE · HEALTH-MID · RANK-UPPER · PHOTO-FINISH · PFAS-LOW · SRC-GW · SYS-MID · BOOK-FULL

  • VIOL-SEVERE 91.4% flagged
  • HEALTH-MID 22.5% health
  • RANK-UPPER #719/3254
  • PHOTO-FINISH ±0.2 pp
  • PFAS-LOW 12.5% detect
  • SRC-GW GW lead 72%
  • SYS-MID 81 systems
  • BOOK-FULL 7/7 fields

Nearest flagged-rate peer: San Bernardino County (+ 0.2 pp flagged-rate)

According to EPA SDWIS county population served used on /counties, Lake County ranks #719 of 3,254 counties by people served, and #43 of 58 counties in California. See methodology · corpus placement.

Lake County standing, lower-flagged corpus third

Flagged-system rate 91.4% is at or below the corpus lower third (≤ 92.7% flagged) across 2,973 counties with ≥3 SDWIS systems . Health-based share 22.5% is health-based share in the middle third (≤ 24.5%) . UCMR5 detect rate 12.5% is UCMR5 detect rate in the tested-pool middle third (≤ 33.3%) . Population served ranks #719 of 3,254 · #43 of 58 in California.

Flagged-rate neighbourhood around Lake County

Lowest/highest poles plus in-state counties nearest Lake County on % of SDWIS systems with ≥1 violation. Full ladder: /counties.

0% 20% 40% 60% 80% 100% Alpine · lowest San Bernardino · near Madera · near Sutter · highest 70% 91.4% 91.5% 91.6% 91.7% 91.9% 97.1%

Source: EPA SDWIS (county aggregates) As of 2026-05-15

Water Systems

System Name Population Violations PFAS
Highlands Mutual Water Company 7,772 23 Clean
Hidden Valley Lake Csd 6,235 2 Clean
Konocti County Water District 5,928 3 Detected
Lakeport, City Of 4,762 9 Clean
Golden State Water Co.-Clearlake System 4,644 2 Clean
Mt. Konocti Mutual Water Company 4,360 14 Clean
Kelseyville Co Waterworks District 3 4,102 0 Clean
Lake County CSA 21 - North Lakeport 4,046 5 -
Cobb Area County Water District 3,515 12 -
Nice Mutual Water Company 2,929 6 -
Clearlake Oaks County Water District 2,359 21 -
Lucerne Water Co. - Cal Water Service 2,129 10 Clean
Lake County CSA 20 - Soda Bay 2,003 1 -
Callayomi County Water District 1,598 8 -
Lake County CSA 2 - Spring Valley 1,531 23 -
Buckingham Park Water District 1,521 24 -
Lower Lake County Water District 1,326 12 -
Lakeside County Park 1,000 12 -
Upper Lake County Water District 989 7 -
Rotten Robbie 899 4 -
Loch Lomond Mutual Water Co 693 26 -
Harbor View Mutual Water Company 550 73 -
Lake County CSA 13 - Kono Tayee 449 4 -
Harbin Hot Springs 401 20 -
Lakeport Cinemas 400 16 -
Anderson Springs Csd 373 31 -
Huttopia Six Sigma Campground 370 0 -
Cache Creek Vineyards 310 0 -
Glenhaven Mutual Water Company 300 19 -
Konocti Shores 277 26 -
Cal 20 Village and Meadow Pointe Park 255 30 -
Clear Water Mutual Water Company 252 46 -
Le Trianon Resort 243 24 -
Mandala Water System 212 18 -
Westgate Petroleum 210 4 -
Saratoga Springs Retreat Center 208 8 -
Reel in Resort 200 40 -
Walnut Cove Mobile Estates 200 22 -
Jitter Bean Coffee 160 4 -
Konocti Harbor Resort 155 9 -
Pier 1900 Homeowner's Association 152 7 -
Bella Lago Mobile Home Park 152 33 -
Corinthian Bay Mutual Water Company 150 21 -
Lake Pillsbury Resort & Marina Inc 150 24 -
Larsen's Office Complex 112 17 -
Usfs-Sunset Point Campground 110 3 -
Thomas Water System 110 2 -
Westwind Mobile Home Park 104 45 -
Lodge at Blue Lakes 100 12 -
Cdf-Konocti Conservation Camp No. 27 100 29 -

Compare beyond California

Lower-flagged peers for Lake County

Cross-state counties nearest Lake County on flagged-system share (91.4%) and cumulative violation count (1,460). In-state neighbours stay on the compliance plate above.

Similar flagged-system rate

Nearest cross-state counties by % of SDWIS systems with at least one violation on record.

4 peers

Similar violation load

Nearest cross-state counties by cumulative SDWIS violation count (all systems in the county).

4 peers

Read our methodology · Check your water system - how this data is sourced, computed, and verified.

Data sourced from EPA SDWIS and UCMR5 PFAS monitoring data. See our methodology for details. Retrieved and formatted by PlainWater

Every figure on PlainWater is rendered directly from EPA SDWIS drinking-water data, no number is typed in by an editor. This page draws directly on EPA SDWIS data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.