Tapcensus

Water quality in Ontario, California

Ontario is in San Bernardino County. 321 active public water systems serve the county; 146 had an EPA violation in the past three years.

Most likely your provider

Chino, City of CA3610012 · Community water system · Surface water purchased · Chino
Serves 90,187 people Rules violated, past 3 years 0 Last sanitary survey May 16, 2022 Distance 5.1 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 San Bernardino County

146 systems, nearest first
SystemServesStatusRules violated, 3 yrDistance
Ontario Municipal Utilities Company
Ontario		 185,010 0 under 0.1 mi
Monte Vista WD
 56,390 0 5.7 mi
California Institution for Men
 10,667 1 5.8 mi
Upland, City of
Upland		 78,376 0 6.3 mi
California Institution for Women
 1,035 0 6.3 mi
Cucamonga Valley Water District
 213,375 0 6.6 mi
San Antonio Water Company
 3,441 0 8.6 mi
West End Consolidated Water Company
 0 0 8.6 mi
San Gabriel Valley WC Fontana
 228,270 0 9.0 mi
Chino Hills, City of
Chino Hills		 76,314 0 9.1 mi
Marygold Mwc
 3,155 1 11.1 mi
West Valley Water District
 96,123 0 12.6 mi
San Antonio Canyon Msc
 119 1 13.9 mi
Rialto, City of
Rialto		 59,264 0 14.0 mi
Snowcrest Heights Imp Assoc
 403 0 14.0 mi
MT Baldy Homeowners Assn.
 350 0 14.1 mi
Terrace Water Company
 2,400 0 15.5 mi
Lytle Springs WC
 475 0 15.8 mi
Colton, City of
Colton		 46,525 0 16.5 mi
Muscoy Mwc No. 1
 13,000 1 16.9 mi
Riverside Highland Water Company
 19,053 1 17.2 mi
Devore WC
 1,574 0 17.7 mi
Gilbert Street Complex
 124 2 18.4 mi
San Bernardino City
San Bernardin0		 214,665 0 18.7 mi
Loma Linda University
 455 0 19.8 mi
All 147 community water systems in San Bernardino County
Non-community systems in San Bernardino County (174: schools, campgrounds, workplaces, restaurants)

These systems serve places you visit rather than homes.

SystemServesStatusRules violated, 3 yrUnresolved
SS Hert Trucking INC
 25 0 0
Lytle Creek Administration Site
 100 5 3
MT Baldy Ski Lift
 1,000 0 0
Bonita Ranch RV Campground
 400 1 0
Arrowhead Regional Medical Center
 4,500 0 0
Hidden Acres
 25 0 0
Socal Mobile Food Facility
Colton 		25 0 0
Mountain Streams RV Park
 16 1 0
Glen Helen Truck Parking Facility
 25 0 0
Applewhite Campground
 3,177 1 0
Petrolink Hwy 138 INC
 25 0 0
Thousand Pines Christian
 28 1 1
Silverwood Japanese Restaurant Sushi & G
 25 1 0
Church of Spiritual Technology
 51 1 0
Best Western Cajon Pass
 34 1 0
Alpine Retreat and Camp
 309 0 0
Forest Lawn Scout Reservation
 200 2 0
Pali Overnight Adventures
 54 0 0
Joshua Inn
 25 1 0
Dovid Oved Retreat Center
 100 0 0
Calvary Chapel Christian Camp
 34 0 0
Ponderosa Pines Christian Camp
 202 0 0
Camp Cedar Crest
 310 1 0
8986 Deep Creek Road
 300 1 0
Green Valley Campground
 3,029 0 0
Burger King #9310
 510 1 0
Snow Valley Mountain Resort
 35 2 0
The High Adobe
 25 0 0
Loch Leven Christian Camp & Conference C
 100 1 0
Parrish Ranch
 25 0 0
OG Investments, LLC
 30 0 0
Los Rios Rancho Water System
 46 1 0
Riley's Log Cabin Farm
 105 1 0
Riley's Farm
 2,400 1 0
Big Pine Flats Admin & Recreation
 417 0 0
Forest Home Christian CC
 100 2 0
EL Mirage School
 50 1 1
Redlands Colony Pipeline Association
 21 1 1
EL Mirage Market
 100 0 0
Lone Wolf Colony
 114 0 0
Camp Cedar Falls
 405 0 0
Cemex Calif Cement LLC VV
 100 1 1
Holland Burger Cafe
 100 2 0
Camp Angelus TR Land Assn
 57 0 0
Seven Oaks MT Resort MHP
 321 0 0
Hanna Flats Campground
 4,850 0 0
YMCA Camp Whittle
 30 1 0
R W Ranch
 101 0 0
DE Benneville Pines
 63 0 0
YMCA Camp Arbolado
 231 0 0
All non-community systems
About this data

Water systems are matched to San Bernardino County, nearest to Ontario 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 or, for systems without one, to the centre of the first town EPA lists the system as serving, from Census Bureau place files.

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.