Tapcensus

Water quality for ZIP code 93409

San Luis Obispo County, California, one of 23 ZIP codes in the county. 172 active public water systems serve the county; 54 had an EPA violation in the past three years.

Most likely your provider

San Luis Obispo Water Department CA4010009 · Community water system · Surface water
Serves 49,534 people Rules violated, past 3 years 0 Last sanitary survey Oct 16, 2024
View system details EPA facility report

Other community water systems in San Luis Obispo County

71 systems, largest first
SystemServesStatusRules violated, 3 yr
Atascadero Mutual Water CO
 33,307 0
City of Paso Robles Water Division
 31,176 0
City of Arroyo Grande Utilities Division
 17,963 1
California Mens Colony
 15,000 0
Nipomo Comm Services Dist
 13,771 0
City of Grover Beach Public Works Dept
 12,701 0
Morro Bay PW Dept Water Division
 10,757 0
Templeton Csd
 8,041 0
Pismo Beach Water Department
 7,944 2
Oceano Comm Services Dist.
 7,598 0
Los Osos Community Services District
 7,086 0
Cambria Comm Services Dist
 6,038 0
Golden State Water Company los Osos
 5,942 0
Golden State Water Company Nipomo
 4,512 0
Woodlands Development
 3,862 0
San Miguel Community Services District
 3,019 0
Heritage Ranch Csd
 2,956 1
Cayucos Beach Mutual Water Company
 2,567 0
Nacimiento Water Company
 2,191 3
Morro Rock Mutual Water CO
 2,181 0
Golden State Water Company-Cypress Ridge
 2,032 0
Avila Beach Community Services District
 1,630 0
San Miguelito Mwc
 1,600 1
Golden State Water Company Edna
 1,495 0
Slo Cwwd No. 23 Santa Margarita
 1,291 0
All 72 community water systems in San Luis Obispo County
Non-community systems in San Luis Obispo County (100: schools, campgrounds, workplaces, restaurants)

These systems serve places you visit rather than homes.

SystemServesStatusRules violated, 3 yrUnresolved
Brecon Estate
San Simeon 		9,012 0 0
Grosso Kresser Winery
San Simeon 		3,606 0 0
Tiger Water Supply
 1,600 0 0
Caltrans Shandon Rest Stop
 1,300 1 0
Pg&e
 1,200 1 1
Montana de Oro State Park
 990 1 0
Coastal Christian School
 650 0 0
Hearst Memorial State Beach
 500 0 0
The Anderson
Cayucos 		500 0 0
Vines R.v. Resort
 400 0 0
Fiero Lane Water Company, Inc.
 324 0 0
Branch Elementary School
 253 0 0
Cal Shasta Club
 240 0 0
Hearst Monument State Park
 215 0 0
Parrish Family Winery
 207 0 0
Jack Ready Imagination Park
Cayucos 		200 0 0
Octagon Barn Center Association
 200 0 0
Strasbaugh, INC
 200 1 0
Sycamore Mineral Springs Resort
 200 1 1
Opolo Water System
San Simeon 		150 0 0
Santa Margarita Recreation Area
 150 0 0
Vachell Water System
 150 1 1
Christmas Cove
 132 0 0
San Simeon Estate Winery
San Simeon 		132 0 0
Calipaso Winery
Cayucos 		130 0 0
J Lohr Winery
 125 0 0
Port San Luis Harbor District
 125 0 0
Madonna Inn Water Company
 120 3 1
Paso Robles RV Ranch
 105 1 0
Creston Elementary School
 100 0 0
Lopez Recreation Area
 100 0 0
Noll Properties
 100 0 0
Pleasant Valley Elementary
 100 1 0
Ragged Point Inn
 100 1 0
LE Cuvier Winery
Cayucos 		92 0 0
Greenheart Farms
 91 0 0
Talley Farms Labor Housing
 90 0 0
Tri Counties Club
 87 2 0
Zoo Med-Winterhaven
Cayucos 		80 1 0
Center of Effort Winery
 75 0 0
Usasa-Pom Enclave Camp Roberts
 75 0 0
Santa Margarita KOA
 70 0 0
Paso 360
 65 0 0
Laetitia Vineyard & Winery INC
 62 0 0
Santa Margarita Ranch Headquarters
Cayucos 		62 0 0
Ball Tagawa Growers
 60 0 0
Toyota San Luis Obispo
 57 0 0
Booker Winery
Cayucos 		56 0 0
Carpenter Winery
Cayucos 		54 0 0
Mt. Olive Organic Farm
Cayucos 		51 0 0
All non-community systems
About this data

Water systems are matched to San Luis Obispo County, the county this ZIP code lies in, largest first. Your exact provider depends on your address and connection; the largest community water system in a county is usually the city or town utility.

ZIP code areas and town boundaries come from the U.S. Census Bureau's 2020 ZCTA files.

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.