PlainWater
Counties → California

Marin County, California

Water Systems
49
Population Served
285,765
Total Violations
805
449 health-based
PFAS Detected
1
of 4 tested

Violation Analysis

79.6%
Systems with Violations
16.4
Avg Violations per System
55.8%
Health-Based Violations

Water Source Types

GW
33 systems (67%)
SW
16 systems (33%)

PFAS Contamination

4
Systems Tested
1
PFAS Detected
25.0%
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

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

No violations on record (10) One or more violations (39)

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
Marin Municipal Water District 186,895 1 Clean
North Marin Water District 61,691 6 Clean
Nps Ggnra 18,447 22 Clean
Bolinas Community PUD 2,483 142 Clean
North Marin WD - Pt. Reyes 1,841 3 -
Csp - Angel Island St Park 1,622 0 -
Nps Prns - Beaches 1,560 76 -
Inverness Public Utility Dist 1,445 99 -
Nps Prns - Lighthouse 1,202 7 -
Nps Prns - Glen and Wildcat Campgrounds 1,200 33 -
Lawson S Landing 946 14 -
Stinson Beach County Wtr Dist 583 7 -
Csp - Mt Tam Theatre Well 504 5 -
Csp - Tomales Bay St Park 503 2 -
Tomales High School 427 7 -
Coast Springs - Cal. Water Service (Puc) 388 23 -
Nps Prns - Five Brooks 365 6 -
Muir Beach Community 336 10 -
Nps Prns - Laguna System 316 10 -
Csp - Samuel Taylor St Park 310 3 -
Skywalker Ranch 250 9 -
Tomales Elem & Middle School 225 6 -
Walker Creek Ranch Educational Center 212 21 -
Estero Mutual 206 88 -
Hog Island Oyster Co. 172 0 -
Marin French Cheese Co 143 3 -
Csp - Marconi Conference Center 120 0 -
William Tell House 110 2 -
Nicasio Ranch LLC 104 7 -
Tony S Seafood Restaurant 103 3 -
Camp Tamarancho 101 2 -
Nick's Cove 90 4 -
Tomales Tin Building 82 6 -
Green Gulch Farm 75 6 -
Csp - Mt Tam East Peak System 75 0 -
Nps Prns - Sky Camp Campground 75 0 -
McEvoy Ranch Water System 66 0 -
Audubon Canyon Ranch - Mgp Picher 50 27 -
Audubon Canyon Ranch - Mgp Volunteer 50 27 -
Marshall Boat Works 50 0 -
Tomales Church of the Assumption 50 0 -
Maif - Marshall Aqua Improvement Forum 50 0 -
Nicasio School 48 56 -
Slide Ranch 47 14 -
Nicasio Valley Ranch Mutual 36 31 -
Blue Mountain Center 35 9 -
Shoreline School Dist: Bus Garage 26 2 -
Diekmann's General Store 25 0 -
Devils Gulch Ranch Water System 25 6 -

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 Marin County? ▼
Marin County has 805 total drinking water violations across 49 water systems, of which 449 are health-based violations. 79.6% of systems have at least one violation.
How many people get water from Marin County systems? ▼
Water systems in Marin County serve approximately 285,765 people through 49 public water systems.
Has PFAS been detected in Marin County water? ▼
Of 4 water systems tested for PFAS in Marin County, 1 had PFAS detected (25.0% detection rate).
What types of water sources supply Marin County? ▼
Water systems in Marin County use GW (33 systems), SW (16 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. 55.8% of Marin 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.