PlainWater
Counties → California

Mendocino County, California

SDWIS compliance plate

Sheet CA045 · Mendocino County 147 sys · 1,646 viol · #658/3254

VIOL-SEVERE · HEALTH-MID · RANK-UPPER · BELOW-PEER · PFAS-LOW · SRC-GW · SYS-LARGE · BOOK-FULL

  • VIOL-SEVERE 77.6% flagged
  • HEALTH-MID 23.1% health
  • RANK-UPPER #658/3254
  • BELOW-PEER 1.5 pp cleaner
  • PFAS-LOW 12.5% detect
  • SRC-GW GW lead 71%
  • SYS-LARGE 147 systems
  • BOOK-FULL 7/7 fields

Nearest flagged-rate peer: Contra Costa County (+ 1.5 pp flagged-rate)

According to EPA SDWIS county population served used on /counties, Mendocino County ranks #658 of 3,254 counties by people served, and #40 of 58 counties in California. See methodology · corpus placement.

Mendocino County standing, lower-flagged corpus third

Flagged-system rate 77.6% is at or below the corpus lower third (≤ 92.7% flagged) across 2,973 counties with ≥3 SDWIS systems . Health-based share 23.1% 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 #658 of 3,254 · #40 of 58 in California.

Flagged-rate neighbourhood around Mendocino County

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

0% 20% 40% 60% 80% 100% Alpine · lowest Contra Costa · near Merced · near Sutter · highest 70% 77.6% 79.1% 79.6% 79.8% 80% 97.1%

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

Water Systems

System Name Population Violations PFAS
Ukiah, City Of 16,607 4 Detected
Fort Bragg, City Of 6,919 12 Clean
Willits, City Of 6,175 28 Clean
Millview County Water District 5,500 6 Clean
Redwood Valley County Water District 5,200 12 Clean
Willow County Water District 3,797 7 Clean
Brooktrails Township Csd 3,632 7 Clean
North Gualala Water Company 2,593 11 -
Rogina Water Company Inc. 2,554 7 -
Csp-Van Damme State Park 2,004 7 -
U.S. Army Corps-Lake Mendo (Bushay Site) 2,000 2 -
U.S. Army Corps-Lake Mendo (Kyen Cmpgrd) 1,500 6 -
Csp-Mackerricher State Park 1,416 10 -
Laytonville County Water District 1,152 34 -
Hopland Public Utility District 1,076 27 -
Mendocino School District- Mendocino 579 9 -
Dolphin Isle Marina 560 12 -
Calpella County Water District 548 11 -
Tesoro 68137 508 2 -
Csp-Standish Hickey State Rec Area 503 9 -
Mendocino County Fairgrounds 500 2 -
Csp-Mendocino Headlands-Sea Arch 500 0 -
Point Arena Water Works 459 5 -
Csp-Pt. Cabrillo Light Station Shp 430 2 -
Albion River Campground 425 17 -
Wente Scout Reservation 422 15 -
Csp-Manchester State Park 420 7 -
Moss Cove Rest Stop (Caltrans) 400 0 -
Csp-Mendocino Woodlands 400 8 -
City of 10,000 Buddhas 400 29 -
Elk County Water District 380 10 -
Csp-Westport State Beach 370 6 -
Westport County Water District 369 55 -
Hidden Pines Campground 362 8 -
Anderson Valley Elementary School 350 16 -
Camp Mendocino 321 18 -
Pine Mountain Mutual Water Co. 310 19 -
Potter Valley School District 309 17 -
Irvine Lodge Rest Stop (Caltrans) 300 2 -
Empire Rest Stop (Caltrans) 300 0 -
U.S. Army Corps-Lake Mendo (Pomo Site) 300 4 -
Anderson Valley High School 300 14 -
Round Valley Elementary School 289 8 -
Camp Navarro 284 6 -
Woodside RV Park 280 20 -
Csp-Mendocino Headlands - Ford House 275 2 -
Manchester Beach KOA 273 4 -
Ridgewood Water System 265 25 -
Green Acres Trailer Park 256 4 -
Irish Beach Water District 254 13 -

Compare beyond California

Lower-flagged peers for Mendocino County

Cross-state counties nearest Mendocino County on flagged-system share (77.6%) and cumulative violation count (1,646). 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.