Tapcensus

California

Sonoma County drinking water quality

445 active public water systems serve 470,466 people in Sonoma County. 369 are compliant, 76 had at least one EPA violation in the past three years, 0 are designated serious violators, and 42 carry a health flag.

Active systems 445 129 community systems
People served 470K by public water systems
Systems with violations 76 17% of active systems, past 3 years
Serious violators 0 42 systems carry a health flag

Needs attention

Sea Ranch Water Company,the (puc) CA4910007 · Community water system · Serves 1,287 3 rules violated in the past three years. Unresolved: Lead and Copper Rule Revisions (LCRR).
Diamond a Mutual Water Company CA4900562 · Community water system · Serves 640 1 rule violated in the past three years. Unresolved: Lead and Copper Rule Revisions (LCRR).
Cazadero Water Company, Inc. (puc) CA4900508 · Community water system · Serves 525 3 rules violated in the past three years. Unresolved: Copper, Free, Lead and Copper Rule (LCR), and Surface Water Treatment Rule (SWTR).
Oak Grove School CA4900703 · Non-Transient non-community system · Serves 500 1 rule violated in the past three years. Unresolved: Lead and Copper Rule Revisions (LCRR).
U.s. Coast Guard Training Center CA4910701 · Community water system · Serves 469 1 rule violated in the past three years. Unresolved: Lead and Copper Rule Revisions (LCRR).
Rincon Valley Mobile Estates CA4900600 · Community water system · Serves 460 1 rule violated in the past three years. Unresolved: Lead and Copper Rule Revisions (LCRR).
Willowside School CA4901156 · Non-Transient non-community system · Serves 460 1 rule violated in the past three years. Unresolved: Lead and Copper Rule Revisions (LCRR).
Mobile Home Estates CA4900720 · Community water system · Serves 403 2 rules violated in the past three years. Unresolved: Lead and Copper Rule Revisions (LCRR).
Olivet Elementary School CA4900699 · Non-Transient non-community system · Serves 400 2 rules violated in the past three years. Unresolved: Lead and Copper Rule (LCR) and Lead and Copper Rule Revisions (LCRR).
Gravenstein School District-Gravenstein CA4900708 · Non-Transient non-community system · Serves 398 1 rule violated in the past three years. Unresolved: Lead and Copper Rule Revisions (LCRR).

32 more systems with a serious violator or health flag designation are in the lists below.

Community water systems

129 systems, largest first
SystemServesStatusRules violated, 3 yrUnresolved
Santa Rosa, City of
Santa Rosa 		178,452 0 0
Petaluma, City of
Petaluma 		61,427 0 0
Rohnert Park, City of
Rohnert Park 		43,821 0 0
Windsor, Town of
 25,561 0 0
Valley of the Moon Water District
 23,140 0 0
Healdsburg, City of
Healdsburg 		10,972 0 0
Sonoma, City of
Sonoma 		10,619 1 1
Cloverdale, City of
Cloverdale 		8,710 1 1
California-American Larkfield (puc)
 7,911 0 0
Sebastopol, City of
Sebastopol 		7,522 0 0
Cotati, City of
Cotati 		7,290 0 0
Sweetwater Springs Cwd Guerneville
 5,156 0 0
Russian River County Water District
 4,150 0 0
Forestville Water District
 3,717 1 0
Sweetwater Springs Cwd Monte Rio
 3,531 0 0
Penngrove Water Company (puc)
 1,742 0 0
Sonoma State University
 1,500 0 0
Sea Ranch Water Company,the (puc)
 1,287 3 1
Camp Meeker Water System
 1,171 0 0
Sonoma County Csa 41-Fitch Mountain
 1,115 1 0
Bodega Bay Public Utility District
 1,069 0 0
California-American Geyserville (puc)
 1,050 0 0
Kenwood Village Water Company (puc)
 1,029 0 0
Canon Manor Water System
 828 0 0
Moon Valley Water System
 691 0 0
Diamond a Mutual Water Company
 640 1 1
Odd Fellows Recreation Club
 557 0 0
Armstrong Valley-Cal Water Service (puc)
 539 0 0
Willowside Mutual Water Company
 528 0 0
Cazadero Water Company, Inc. (puc)
 525 3 2
U.s. Coast Guard Training Center
 469 1 1
Rincon Valley Mobile Estates
 460 1 1
Bennett Ridge Mutual Water Company
 439 0 0
Santa Rosa Mobile Estates
 420 0 0
Leisure Mobile Home Park
 410 0 0
Sonoma County Csa 41-Jenner
 406 0 0
Mobile Home Estates
 403 2 1
Occidental Community Services District
 383 0 0
Sereno del Mar Water Company (puc)
 375 0 0
Heights Mutual Water Company
 363 0 0
EL Portal Mobile Estates
 344 1 1
Colonial Park
 342 0 0
Sonoma County Csa 41-Salmon Creek
 327 0 0
Branger Mutual Water Company, Inc.
 300 1 1
Holland Heights Mutual Water Company
 300 0 0
Palomino Lakes Mutual Water Co.
 300 0 0
Gill Creek Mutual Water Company
 290 0 0
Belmont Terrace Mutual Water Company
 287 0 0
Happy Acres Mutual Benefit Water System
 260 0 0
Mountain View Mobile Estates, LLC
 250 0 0
Non-community systems (316: schools, campgrounds, workplaces, restaurants)

These systems serve places people visit rather than homes.

SystemServesStatusRules violated, 3 yrUnresolved
Csp-Salt Point State Park
 3,513 0 0
Csp-Fort Ross State Park
 3,501 0 0
Sutter Santa Rosa Regional Hospital
 1,000 0 0
KOA Petaluma
 713 0 0
Urj Camp Newman
 705 0 0
Jehovah's Witnesses Hall
 650 0 0
Csp-Armstrong Redwoods State Reserve
 611 0 0
Csp-Wrights Beach State Park
 502 0 0
Cline Cellars
 500 0 0
Oak Grove School
 500 1 1
Willowside School
 460 1 1
Casini Ranch Campground
 442 0 0
Csp-Goat Rock State Beach
 402 0 0
Olivet Elementary School
 400 2 2
Twin Hills School Dist-Apple Blossom Sch
 400 0 0
Twin Hills School Dist-Twin Hills School
 400 0 0
Gravenstein School District-Gravenstein
 398 1 1
Bellevue Union Sch Dist-Bellevue School
 380 0 0
Union Hotel
 350 0 0
Northwest Prep Charter School
 325 1 0
Sebastopol Charter School
 310 0 0
Ocean Cove Store & Campground
 304 0 0
Petrified Forest
 304 0 0
Sikh Gurdwara Santa Rosa
 302 0 0
Cazadero Performing Arts Camp
 301 0 0
Summerfield Waldorf School
 301 0 0
Lombardi's Deli & Bbq
 300 0 0
Salmon Creek Middle School
 300 2 0
The Lodge at Sonoma
 300 1 0
Korbel Brothers Winery
 296 0 0
Gravenstein School District-Hillcrest
 289 1 1
Naco West Russian River Preserve
 263 0 0
River Bend Resort
 255 0 0
Sonoma County Parks-Vet. Memorial Beach
 252 0 0
Adair Kunde, LLC
 250 0 0
Bacchus Landing Cellars
Healdsburg 		250 0 0
Catholic Charities Cyo Camp
 250 0 0
Santa Rosa Golf & Country Club
 250 0 0
Cinnabar Elementary School
 228 0 0
Liberty School
 225 0 0
Francis Coppola Winery
 222 1 1
Csp-Sugarloaf Ridge State Park
 204 0 0
Adair Viansa, LLC
 200 0 0
Alexander Valley Union School District
 200 0 0
Geyserville Newtech Academy School
 200 1 1
Johnson's Beach Resort
 200 0 0
Presentation School
 200 1 1
Sonoma Warehousing
 200 0 0
Cornerstone Sonoma
 175 0 0
Dunham School
 175 1 1
Landmark Vineyards, Ltd.
 175 0 0
Manzana Products Company, Inc.
 175 0 0
West Side Union School District
 175 0 0
Gambonini Family Ranch
 170 0 0
Russian River Vineyards & Restaurant
 157 0 0
Sebastopol Vineyards
 156 0 0
Adair B.r. Cohn, LLC
 155 0 0
Sonoma State U.-Fairfield Osborn Pres
 151 0 0
Calpine (geysers Administration Center)
 150 0 0
Camp Liahona Redwoods
 150 0 0
Hop Kiln Winery
 150 0 0
Macrostie Winery and Vineyard
 150 0 0
Nicholson Ranch Winery
 150 0 0
Rodney Strong Vineyards
 150 0 0
Matanzas Creek Winery
 139 0 0
Imagery Estate Winery
 135 0 0
Rams Gate Winery
 135 0 0
Csp-Petaluma Adobe State Historic Park
 134 0 0
Csp-Jack London State Historic Park
 130 0 0
Triple S Ranch
 130 0 0
Ledson Winery and Vineyards
 128 0 0
Duncans Mills Camping Club
 127 0 0
Foley Family Wines Chateau St. Jean
 125 1 1
E & J Gallo Winery-Sonoma
 124 0 0
Boisset Buena Vista Winery
 122 0 0
Traditional Medicinals, Inc.
 120 0 0
Hessel Church
 116 0 0
Jacuzzi Winery
 108 0 0
Gary Farrell Winery
 106 0 0
Anaba Winery
 105 0 0
Vineburg Deli & Grocery
 104 0 0
Jan Klebe
 101 0 0
Starlite Winery
 101 0 0
Broadway Market
 100 0 0
Cloverdale Campground
 100 0 0
Cloverleaf Ranch Summer Camp
 100 0 0
Fort Ross School District
 100 0 0
Fort Ross Vineyard
 100 0 0
Geyserville Winery
 100 0 0
Horicon School
 100 0 0
Lynmar Winery
 100 0 0
Midgley's Country Flea Market
 100 0 0
Molino Corner Water System
 100 0 0
Ocean Cove Lodge Bar & Grill
 100 0 0
Petaluma Livestock Auction Yard
 100 0 0
Sequoia Water Company
 100 0 0
Valley of the Moon Plaza Shopping Center
 100 0 0
Safari West
 99 0 0
Friedman Brothers Hardware
 95 0 0
Santa Rosa Liquor and Deli
 95 0 0
All 316 in the systems table
Inactive systems (318, no longer operating or reporting)

Kept for the record and excluded from the county totals above. Browse inactive systems.

About this data

Totals cover active systems. Systems serving more than one county are counted in each county. EPA counts the rules a system was in violation of, not the individual violations; one rule can carry several.

Source: the U.S. EPA's Enforcement and Compliance History Online system (ECHO), which publishes the federal Safe Drinking Water Information System. EPA's terms and values are shown as published. The California records are from EPA's data refresh of Oct 7, 2026; EPA refreshes this data quarterly, and states report to EPA with a lag of three to six months, so the newest violations may not appear yet. Retrieved from ECHO on Oct 11, 2026.