Tapcensus

Water quality for ZIP code 94595

ZIP 94595 covers Walnut Creek, Saranap, and Castle Hill in Contra Costa County, California, one of 43 ZIP codes in the 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 11.1 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
Moraga Heights Mutual Water
 66 0 5.9 mi
Wilcox Station Ranch
 31 1 5.9 mi
City of Martinez
Martinez		 31,015 0 9.0 mi
Golden State Water Company Bay Point
 23,765 0 12.4 mi
Bella Vista Water Sys
 93 3 13.4 mi
Riverview Mobile Home Park
 126 1 13.5 mi
City of Pittsburg
Pittsburg		 62,500 0 13.8 mi
Clayton Palms Water
 549 1 15.1 mi
Casa Medanos Water System
 45 1 15.4 mi
City of Antioch
Antioch		 116,781 0 16.6 mi
Doubletree Ranch Water System
 66 0 17.0 mi
Brentwood
Brentwood		 64,513 0 19.6 mi
Randall-Bold Water Treatment Plant
 1 0 19.6 mi
Ccwd/brentwood Wtp
 0 0 19.7 mi
Colonia Santa Maria
 32 2 20.8 mi
Big Oak Mobile Home Park Water
 156 0 21.8 mi
Diablo Water District
 47,158 0 22.0 mi
Knightsen Community Water System
 73 0 23.2 mi
Camino Mobilehome
 210 0 23.3 mi
Dutch Slough Water Works
 49 1 24.7 mi
Angler S Ranch #3
 60 1 24.7 mi
Anglers Subdivision 4
 99 1 25.0 mi
Town of Discovery Bay
 16,790 0 25.3 mi
Orwood Resort
 350 2 25.4 mi
Bethel Island Mutual Water CO
 123 1 25.4 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
Wildwood Acres Resort
 28 0 0
Old Borges Ranch Water Sys
 75 0 0
Ebrpd Little Hills
 66 0 0
Canyon School
 80 1 1
Ebrpd Old Briones Regional Park
 47 0 0
Mount Diablo State Park
 364 0 0
Concord MT Diablo Trailride Assoc.
 120 0 0
Willow Pass Bussiness Park Water System
 60 1 1
All Star Academy of Danville
 30 0 0
Ebrpd Black Diamond Mines
 74 0 0
Ebrpd Bay Point Regional Shoreline
Pittsburg 		105 0 0
McAvoy Yacht Harbor
 55 0 0
Ebrpd Morgan Territory
 57 0 0
Ebrpd Round Valley Water System
 82 0 0
Los Vaqueros Marina Bldg
 180 0 0
Bridgehead Cafe
 75 0 0
Los Vaqueros Interpretive Center
 30 0 0
Bethel Missionary Baptist
 54 0 0
Bay Standards
 41 1 1
Knightsen Elementary School
 350 0 0
Country Junction Deli
 200 0 0
Byron United Methodist
 50 0 0
Gas N Save
 120 0 0
Byron Roadhouse
 25 0 0
Excelsior Middle School
 600 0 0
Marin Food Specialties
 25 0 0
Byron Corners INC
 205 0 0
Byron Airport
 35 0 0
New Life Marina
 80 0 0
Byron Inn
 60 0 0
Tess Farm Market
Brentwood 		25 0 0
Delta Sportsman
 150 0 0
Sunset Marina
 30 0 0
Bethel Market
 100 0 0
Delta Bar and Grill
 100 0 0
Dwr Delta Field Division Banks PP
 180 0 0
Bethel Baptist Church
 75 0 0
Willowest Marina WS
 35 0 0
Bethel Harbor
 45 0 0
Brentwood Marina
 30 0 0
Sugar Barge Marina
 150 0 0
Holland Riverside Marina
 45 0 0
Cruiser Haven Marina
 75 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, the county this ZIP code lies in, nearest to the ZIP code's centre 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.

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.