Tapcensus

Water quality for ZIP code 91741

ZIP 91741 covers Glendora and San Dimas in Los Angeles County, California, one of 295 ZIP codes in the county. 271 active public water systems serve the county; 66 had an EPA violation in the past three years.

Most likely your provider

Glendora-City, Water Dept. CA1910044 · Community water system · Surface water purchased · Glendora
Serves 44,411 people Rules violated, past 3 years 0 Last sanitary survey Jul 29, 2025 Distance 1.6 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 Los Angeles County

198 systems, nearest first
SystemServesStatusRules violated, 3 yrDistance
Suburban Water Systems-Glendora
 5,301 0 3.2 mi
Metropolitan Water Dist. of So. Cal.
 0 0 3.9 mi
Gswc-San Dimas
 56,564 0 4.2 mi
Covina Valley Water Company Wholesale
 0 0 4.6 mi
Azusa Light and Water
 110,044 0 4.9 mi
LA Verne, City WD
La Verne		 31,334 0 5.0 mi
Suburban Water Systems-Covina Knolls
 1,451 0 5.3 mi
Covina-City, Water Dept.
Covina		 33,300 0 5.4 mi
The River Community
 35 2 5.8 mi
Camp Williams-Resort Water
 80 0 6.0 mi
Valencia Heights Water Co.
 7,775 0 6.9 mi
Three Valleys Mwd
 0 0 7.0 mi
Calif State Polytechnical Univ Pomona
 2,668 2 7.0 mi
Cal-Am Water Company Duarte
 24,767 0 7.1 mi
Gswc Claremont
 39,776 0 7.7 mi
Valley County Water Dist.
 68,871 0 7.8 mi
Pomona City, Water Dept.
Pomona		 151,713 0 8.3 mi
Monrovia-City, Water Dept.
Monrovia		 37,931 0 8.6 mi
Valley View Mutual Water Co.
 4,613 0 9.1 mi
Suburban Water Systems-San Jose
 170,523 0 9.4 mi
Walnut Valley Water District
 100,941 0 10.3 mi
Hemlock Mutual Water Co.
 686 2 10.3 mi
Gswc-South Arcadia
 27,430 0 10.8 mi
Sterling Mutual Water Company
 198 2 11.1 mi
LA Puente Valley Cwd
 8,276 0 11.2 mi
All 199 community water systems in Los Angeles County
Non-community systems in Los Angeles County (72: schools, campgrounds, workplaces, restaurants)

These systems serve places you visit rather than homes.

SystemServesStatusRules violated, 3 yrUnresolved
Irwindale Brewery Yard (iby)
 300 0 0
Martin Marietta Southern Calif Aggregate
 51 0 0
Coldbrook Campground
 38 0 0
Usfs-Crystal Lake B-13 Water
 2,000 0 0
Usfs-Chantry Flats-A16 Water
 113 0 0
Usfs-Skyline Park / Mount Wilson A-4
 25 0 0
Henninger Flats
 50 0 0
Usfs-Chilao Main A-9
 50 0 0
Angeles Crest Christian Camp
 112 1 0
Usfs-Red Box Station A-3
 25 0 0
Huttopia Paradise Springs
 302 1 0
Usfs-Jackson Lake V-4
 805 0 0
Mountain High East Ski Area
 150 0 0
Mount Kare Camp/kare Youth League
 59 0 0
Usfs-Big Pines V-2
 54 0 0
Usfs-Appletree Flats V-3
 25 0 0
Camp Elk
 121 0 0
Millard Canyon Improvement Association
 42 1 0
Colby Ranch-United Methodist Camp
 180 0 0
Usfs-Valyermo Ranger Station
 25 1 1
Clear Creek Outdoor Education Center
 105 0 0
Usfs-Monte Cristo Camp T-4
 116 0 0
Saint Andrews Abbey
 210 1 1
Young-Nak Presbyterian Church
 25 0 0
Plant Water Well Rockview Dairy
South Gate 		45 0 0
Rancho los Amigos Hospital
 3,200 0 0
Rancho Ybarra Christian Camp
 73 0 0
1000 Trails / Soledad Canyon Preserve
 812 1 0
General Atomics Aeronautical Gray Butt
 405 0 0
Acton-Agua Dulce Lds Church
 150 0 0
Acton Four Square Church
 50 0 0
Acton la North KOA
 400 0 0
Angeles Shooting Ranges
 490 0 0
Acton Conservation Camp #11
 90 4 0
Desert Aire Golf Course
 80 0 0
Los Angeles World Airports
 180 0 0
Antelope Valley Indian Museum State Park
 506 0 0
Lockheed Martin Skunk Works
 135 0 0
Vasquez Rocks County Park
 30 0 0
Northrop Grumman Corp.
 5,764 1 0
Agua Dulce Women's Club
 50 0 0
Lang Ranch Shopping Center
 28 0 0
Ilead Agua Dulce Charter School
 450 1 1
Wagon Wheel Plaza
 55 1 0
Agua Dulce Water System
 493 0 0
Agua Dulce Winery
 113 0 0
Living Springs Church
 50 0 0
Shepherd of the Hills
 80 0 0
Lancaster National Soccer Center
Lancaster 		500 0 0
LE Chene Restaurant Water System
 100 0 0
All non-community systems
About this data

Water systems are matched to Los Angeles 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.