Tapcensus

Water quality in San Ramon, California

San Ramon is in Contra Costa County. 84 active public water systems serve the county; 21 had an EPA violation in the past three years.

Most likely your provider

Contra Costa Water District CA0710003 · Community water system · Surface water
Serves 210,500 people Rules violated, past 3 years 0 Last sanitary survey Jan 13, 2022 Distance 13.4 mi

Your location is within the outer bounds of this system's EPA service area.

View system details EPA facility report

Other community water systems in Contra Costa County

38 systems, nearest first
SystemServesStatusRules violated, 3 yrDistance
Doubletree Ranch Water System
 66 0 8.1 mi
Clayton Palms Water
 549 1 11.7 mi
Wilcox Station Ranch
 31 1 13.2 mi
Moraga Heights Mutual Water
 66 0 13.5 mi
Colonia Santa Maria
 32 2 16.3 mi
Brentwood
Brentwood		 64,513 0 16.6 mi
City of Antioch
Antioch		 116,781 0 16.6 mi
Camino Mobilehome
 210 0 17.5 mi
Casa Medanos Water System
 45 1 17.6 mi
City of Pittsburg
Pittsburg		 62,500 0 17.6 mi
Riverview Mobile Home Park
 126 1 18.1 mi
Bella Vista Water Sys
 93 3 18.1 mi
Randall-Bold Water Treatment Plant
 1 0 18.3 mi
Golden State Water Company Bay Point
 23,765 0 18.3 mi
Ccwd/brentwood Wtp
 0 0 18.3 mi
City of Martinez
Martinez		 31,015 0 19.0 mi
Big Oak Mobile Home Park Water
 156 0 20.1 mi
Town of Discovery Bay
 16,790 0 20.3 mi
Diablo Water District
 47,158 0 20.3 mi
Knightsen Community Water System
 73 0 20.6 mi
Orwood Resort
 350 2 21.2 mi
Dutch Slough Water Works
 49 1 22.9 mi
Oakley Mutual Water Company
 170 2 22.9 mi
Delta Mutual Water Company
 333 1 23.2 mi
Angler S Ranch #3
 60 1 23.2 mi
All 39 community water systems in Contra Costa County
Non-community systems in Contra Costa County (45: schools, campgrounds, workplaces, restaurants)

These systems serve places you visit rather than homes.

SystemServesStatusRules violated, 3 yrUnresolved
All Star Academy of Danville
 30 0 0
Ebrpd Little Hills
 66 0 0
Mount Diablo State Park
 364 0 0
Ebrpd Morgan Territory
 57 0 0
Old Borges Ranch Water Sys
 75 0 0
Wildwood Acres Resort
 28 0 0
Ebrpd Round Valley Water System
 82 0 0
Concord MT Diablo Trailride Assoc.
 120 0 0
Los Vaqueros Marina Bldg
 180 0 0
Canyon School
 80 1 1
Ebrpd Black Diamond Mines
 74 0 0
Los Vaqueros Interpretive Center
 30 0 0
Ebrpd Old Briones Regional Park
 47 0 0
Byron Airport
 35 0 0
Bay Standards
 41 1 1
Marin Food Specialties
 25 0 0
Byron United Methodist
 50 0 0
Byron Corners INC
 205 0 0
Willow Pass Bussiness Park Water System
 60 1 1
Excelsior Middle School
 600 0 0
Byron Inn
 60 0 0
Country Junction Deli
 200 0 0
Byron Roadhouse
 25 0 0
Dwr Delta Field Division Banks PP
 180 0 0
Bridgehead Cafe
 75 0 0
Bethel Missionary Baptist
 54 0 0
Ebrpd Bay Point Regional Shoreline
Pittsburg 		105 0 0
McAvoy Yacht Harbor
 55 0 0
Tess Farm Market
Brentwood 		25 0 0
Knightsen Elementary School
 350 0 0
Gas N Save
 120 0 0
Cruiser Haven Marina
 75 0 0
Sunset Marina
 30 0 0
Delta Sportsman
 150 0 0
New Life Marina
 80 0 0
Bethel Market
 100 0 0
Delta Bar and Grill
 100 0 0
Holland Riverside Marina
 45 0 0
Bethel Baptist Church
 75 0 0
Brentwood Marina
 30 0 0
Sugar Barge Marina
 150 0 0
Bethel Harbor
 45 0 0
Willowest Marina WS
 35 0 0
Ebrpd Alhambra
 115 0 0
Wahl Family Water System
 65 0 0
About this data

Water systems are matched to Contra Costa County, nearest to San Ramon 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. Distances are measured to the centre of the service area EPA publishes for the system.

Town locations and ZIP code areas come from U.S. Census Bureau 2020 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.