Tapcensus

California

Stanislaus County drinking water quality

192 active public water systems serve 506,514 people in Stanislaus County. 124 are compliant, 68 had at least one EPA violation in the past three years, 1 is a designated serious violator, and 19 carry a health flag.

Active systems 192 61 community systems
People served 507K by public water systems
Systems with violations 68 35% of active systems, past 3 years
Serious violators 1 19 systems carry a health flag

Needs attention

Brethren Heritage School, INC CA5000335 · Non-Transient non-community system · Serves 55 2 rules violated in the past three years. Unresolved: Lead and Copper Rule and Lead and Copper Rule Revisions.
Ceres, City of CA5010028 · Ceres · Community water system · Serves 54,513 1 rule violated in the past three years. Unresolved: Lead and Copper Rule Revisions.
Hughson, City of CA5010008 · Hughson · Community water system · Serves 7,977 2 rules violated in the past three years. Unresolved: Lead and Copper Rule Revisions.
Crows Landing Comm Svc District CA5000005 · Community water system · Serves 500 2 rules violated in the past three years. Unresolved: Lead and Copper Rule Revisions.
Chatom School (eh) CA5000101 · Non-Transient non-community system · Serves 385 1 rule violated in the past three years. Unresolved: Lead and Copper Rule Revisions.
Sunrise Village MHP CA5000095 · Community water system · Serves 339 1 rule violated in the past three years. Unresolved: Lead and Copper Rule Revisions.
Mountain View Elementary School CA5000255 · Non-Transient non-community system · Serves 170 2 rules violated in the past three years. Unresolved: Lead and Copper Rule Revisions.
Sconza Candy Company CA5000179 · Non-Transient non-community system · Serves 170 1 rule violated in the past three years. Unresolved: Lead and Copper Rule Revisions.
Riverbank Lra CA5000211 · Non-Transient non-community system · Serves 156 1 rule violated in the past three years. Unresolved: Lead and Copper Rule Revisions.
Grover Landscape Water System CA5000580 · Non-Transient non-community system · Serves 125 2 rules violated in the past three years. Unresolved: Lead and Copper Rule Revisions.

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

Community water systems

61 systems, largest first
SystemServesStatusRules violated, 3 yrUnresolved
Modesto, City of
Modesto 		218,915 0 0
Turlock, City of
Turlock 		72,888 0 0
Ceres, City of
Ceres 		54,513 1 1
Riverbank, City of
Riverbank 		25,625 0 0
Patterson, City of
Patterson 		24,977 0 0
Oakdale, City of
Oakdale 		23,235 1 0
City of Modesto Salida
Modesto 		14,576 0 0
City of Newman-Water Department
Newman 		12,389 1 0
City of Waterford
Modesto 		8,788 0 0
Hughson, City of
Hughson 		7,977 2 1
Keyes Community Services Dist.
 5,672 0 0
Denair Community Services District
 5,093 0 0
Western Hills Water District/diablo Gran
 2,000 0 0
Oid-Oakdale Rural Water System #1
 1,570 0 0
City of Modesto del Rio
Modesto 		1,346 0 0
City of Modesto South Turlock
Modesto 		1,109 0 0
Waterford-River Pointe
 1,079 0 0
City of Modesto Grayson
Modesto 		917 0 0
Hillsview Homes
 887 1 0
Riverdale Park Tract Csd
 610 1 0
Waterford Hickman
Modesto 		597 0 0
Riverview Mobile Home Estates
 540 2 0
Crows Landing Comm Svc District
 500 2 1
Sunrise Village MHP
 339 1 1
Oid #51 Sunset Oaks #10
 287 0 0
Oid #46 Sunset Oaks
 269 0 0
Park Heights Mutual Water CO
 250 0 0
North Oaks Mutual Water CO
 234 1 1
Casa de Amigos Manufactured Housing Comm
 204 0 0
Tid/ la Grange Water System
 195 0 0
Monterey Park Tract Csd
 186 1 1
City of Modesto Walnut Manor
Modesto 		178 0 0
City of Modesto North Turlock
Modesto 		172 0 0
Knights Ferry Comm. Svc. Dist.
 168 0 0
Olive Lane Mobilehome Park
 153 0 0
Buehner Water System
 150 0 0
Oid #22 Williams Tract
 150 0 0
Mulberry MHP
 148 1 1
Oid #45
 144 0 0
Lazy B Mobilehome Park
 125 1 0
Fisherman's Bend MHP
 120 0 0
City of Modesto Central Turlock
Modesto 		119 0 0
Twin Cypress Mobile Home Park
 112 0 0
Del Rio East HOA Water System
 110 1 1
Oasis Investments
 75 1 0
Westley Csd
 70 1 1
Morningside Mobilehome Park
 67 0 0
4n Mobilehome Park
 65 0 0
Lone Pine MHP
 64 0 0
Country Villa Apts
 60 1 0
Non-community systems (131: schools, campgrounds, workplaces, restaurants)

These systems serve places people visit rather than homes.

SystemServesStatusRules violated, 3 yrUnresolved
Gregori High School
 2,000 0 0
Department of Transportation
 1,000 0 0
Our Lady of Assumption Church
 1,000 0 0
Mesa Elementary School
 860 0 0
Hart Ransom Union School & District
 650 0 0
Woodward Reservoir Water System
 537 0 0
Jehovah's Witness Sierra Vista Cong
 500 0 0
River Oak Grace-Water System
 500 1 0
River Oaks/kingdom Hall
 500 0 0
Ceres Unified/westport School
 450 2 0
Bronco Winery
 400 0 0
Stanislaus Union School Dist
 390 1 1
Chatom School (eh)
 385 1 1
5033 Pentecost
 302 0 0
Covenant Grove Church
 300 0 0
Nmip Fire & Water System, LLC
 300 1 0
Ram Naam Mandali Church of Modesto
 250 0 0
Paradise School
 218 0 0
The Morning Star Company
 200 0 0
Monte Vista Farming
Denair 		188 3 2
Mountain View Elementary School
 170 2 1
Sconza Candy Company
 170 1 1
Riverbank Lra
 156 1 1
Greenlaw Modesto Investors LLC
 142 0 0
Gratton School
 141 0 0
Stratos Way Water Company, INC
 135 0 0
Grover Landscape Water System
 125 2 1
Kiernan Business Center
 120 0 0
Libitzky
 120 1 1
Hughson Nut Company Water System
 110 0 0
Ratto Bros, INC
 110 0 0
Gurudwara Guru Nanak Sahib
 109 0 0
Oakdale Cheese & Specialties
 108 0 0
Shiloh School District
 105 1 0
Kingdom Hall Jehovah Witness
 100 0 0
Roberts Ferry School Cafeteria
 100 0 0
Sikh Temple Modesto-Ceres
 97 0 0
Wood Colony Christian School
 90 1 1
At&t Water System
 80 1 1
Valley Home School Texas
 80 1 1
Duarte Nursery INC Water System
 75 2 1
Cebro Frozen Foods (eh)
 70 0 0
Grace Community Christian Church
 70 0 0
New Hope Church of the Nazarene
 70 0 0
Frazier Nut Farms, Inc.
 64 1 0
Mid Valley Nut CO
Hughson 		60 3 2
Brethren Heritage School, INC
 55 2 2
One Stop WS
 50 1 0
Rbvon
 50 0 0
Excell Center
 45 1 1
Liberty Baptist Church
 45 1 0
Rolling Hills Nut Company
Modesto 		45 0 0
Darling Ingredients Turlock
 43 1 1
The Fruit Yard Restaurant
 43 1 1
Chemurgic Agricultural Chemicals, Inc.
 42 2 2
Lakewood Memorial Park & Funeral Home
 40 1 1
Storer Transportation
 40 1 0
Foster Farms-Ellenwood Hatchery
 38 0 0
Patterson Cemetery District
Patterson 		37 0 0
Sterling Industrial
 35 1 1
Bloomingcamp Water System
 34 1 0
Turlock Sportsman's Club
 32 0 0
Fink Road Landfill Stanislaus
 31 0 0
California Nut Company
 30 1 1
Jennings Wwtp
 30 1 1
Rainbow Farms
 30 1 1
Tds California
 30 1 1
Golden Arco
 28 0 0
Lander Veterinary Clinic
 27 0 0
McHenry Business Park
 27 2 1
4937 Beckwith Water System
 26 0 0
5801 McHenry Ave
 26 0 0
Basso Bridge Fishing/boating Access
 26 0 0
Beckley Lyons Water System
 26 0 0
City of Oakdale -Kerr Park
 26 0 0
Eastin
 26 2 0
Farmers' Den /market
 26 1 0
Fox Grove Fishing Access
 26 0 0
Frank Raines Park Ohv
 26 0 0
Gawfco Enterprises, Inc.
 26 0 0
Hamlet Motel
 26 1 0
Joe's Food Mart Water System
 26 0 0
Joe's Travel Plaza (eh)
 26 0 0
Knights Ferry Recreation Area
 26 0 0
LA Grange Park-Ohv
 26 0 0
Log Cabin
 26 0 0
Orange Blossom Recreation Area
 26 0 0
Shiloh-Paradise Baseball for Youth
 26 1 0
Shively's Bar & Grill
 26 1 0
Smart Stop Food Mart (eh)
 26 0 0
Taqueria Rancho Alegre
 26 0 0
Valley Home School Pioneer
 26 0 0
VFW Post 5059 Water System
 26 1 1
Whiskey River Saloon
 26 0 0
Avidwater, LLC
 25 0 0
Bel Passi Baseball
 25 0 0
Burchell Nursery, INC
 25 0 0
California Transplants LLC
 25 0 0
Charity Way Water System
Modesto 		25 1 1
Country Store Water System
 25 0 0
All 131 in the systems table
Inactive systems (264, 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.