PlainWater
Counties → California

Sonoma County, California

Water Systems
440
Population Served
481,120
Total Violations
6,052
1,896 health-based
PFAS Detected
11
of 17 tested

Violation Analysis

83.6%
Systems with Violations
13.8
Avg Violations per System
31.3%
Health-Based Violations

Water Source Types

GW
41 systems (9%)
SW
9 systems (2%)

PFAS Contamination

17
Systems Tested
11
PFAS Detected
64.7%
Detection Rate

PFAS (per- and polyfluoroalkyl substances) are persistent chemicals found in drinking water. The EPA has set enforceable limits for several PFAS compounds under UCMR5 monitoring.

Compliance Snapshot

Sonoma California water systems by violation status, EPA SDWIS records.

No violations on record (4) One or more violations (46)

Violation history is cumulative, many flagged systems have already returned to compliance. Detail pages show per-system context.

Water Systems

System Name Population Violations PFAS
Santa Rosa, City Of 175,396 4 Clean
Petaluma, City Of 60,781 4 Clean
Rohnert Park, City Of 43,821 561 Detected
Windsor, Town Of 25,561 6 Clean
Valley of the Moon Water District 23,107 9 Detected
Sonoma, City Of 11,725 17 Detected
Sonoma State University 10,986 22 Clean
Healdsburg, City Of 10,985 11 Detected
Cloverdale, City Of 10,398 24 Clean
California-American Larkfield (Puc) 7,913 6 Clean
Sebastopol, City Of 7,522 19 Clean
Cotati, City Of 7,303 3 Clean
Sweetwater Springs Cwd - Guerneville 6,000 7 Clean
Russian River County Water District 4,150 13 Clean
Forestville Water District 3,788 2 -
Csp-Salt Point State Park 3,513 1 -
Csp-Fort Ross State Park 3,501 17 -
Sweetwater Springs Cwd - Monte Rio 3,000 0 -
Penngrove Water Company (Puc) 1,742 19 -
Sonoma County CSA 41-Fitch Mountain 1,265 5 -
Camp Meeker Water System 1,171 0 -
Sea Ranch Water Company,the (Puc) 1,160 11 Detected
Bodega Bay Public Utility District 1,069 7 -
California-American Geyserville (Puc) 1,046 1 Clean
Kenwood Village Water Company (Puc) 1,029 8 -
Sutter Santa Rosa Regional Hospital 1,000 0 -
Canon Manor Water System 805 6 -
Odd Fellows Recreation Club 757 8 -
Urj Camp Newman 705 7 -
Moon Valley Water System 691 4 -
Jehovah S Witnesses Hall 650 8 -
Diamond a Mutual Water Company 640 18 -
Csp-Armstrong Redwoods State Reserve 611 0 -
Korbel Brothers Winery 546 8 -
Occidental Community Services District 533 25 -
Cazadero Water Company, Inc. (Puc) 525 57 -
Csp-Wrights Beach State Park 502 4 -
Wright Elementary School 500 7 -
Oak Grove School 500 10 -
Cline Cellars 500 10 -
Armstrong Valley-Cal Water Service (Puc) 473 1 -
U.S. Coast Guard Training Center 469 7 -
Rincon Valley Mobile Estates 460 14 -
Willowside School 460 6 -
Willowside Mutual Water Company 448 16 -
Casini Ranch Campground 442 9 -
Bennett Ridge Mutual Water Company 439 9 -
Sereno del Mar Water Company (Puc) 435 19 -
Sonoma County CSA 41-Salmon Creek 427 15 -
Santa Rosa Mobile Estates 420 9 -

Other Counties in California

Los Angeles County
276 systems · 10,109,089 served · 3,972 violations
San Diego County
197 systems · 3,744,323 served · 4,832 violations
Orange County
46 systems · 3,201,893 served · 507 violations
Riverside County
201 systems · 2,839,125 served · 6,103 violations
San Bernardino County
318 systems · 2,830,626 served · 4,611 violations
Alameda County
27 systems · 2,249,634 served · 275 violations

Drinking Water Guides

Frequently Asked Questions

How many water violations are in Sonoma County? ▼
Sonoma County has 6,052 total drinking water violations across 440 water systems, of which 1,896 are health-based violations. 83.6% of systems have at least one violation.
How many people get water from Sonoma County systems? ▼
Water systems in Sonoma County serve approximately 481,120 people through 440 public water systems.
Has PFAS been detected in Sonoma County water? ▼
Of 17 water systems tested for PFAS in Sonoma County, 11 had PFAS detected (64.7% detection rate).
What types of water sources supply Sonoma County? ▼
Water systems in Sonoma County use GW (41 systems), SW (9 systems) as their primary water sources.
Are health-based violations serious? ▼
Health-based violations indicate that drinking water exceeded Maximum Contaminant Levels (MCLs) set by the EPA or failed treatment technique requirements. 31.3% of Sonoma County's violations are health-based. Not all violations indicate immediate health risk, but they require corrective action.
Data Sources & Methodology

Drinking water violation data from the EPA Safe Drinking Water Information System (SDWIS). PFAS testing data from the UCMR5 monitoring program. SDWIS tracks all public water systems regulated under the Safe Drinking Water Act.

Violations are categorized as health-based (Maximum Contaminant Level exceedances, treatment technique failures) or monitoring/reporting violations. Not all violations indicate an immediate health risk.

Read our methodology - 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 Editorial

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.