Tapcensus

Water quality for ZIP code 91740

ZIP 91740 covers Glendora, San Dimas, Citrus, and Charter Oak 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 1.1 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 Los Angeles County

198 systems, nearest first
SystemServesStatusRules violated, 3 yrDistance
Suburban Water Systems-Glendora
 5,301 0 1.2 mi
Covina Valley Water Company Wholesale
 0 0 1.9 mi
Gswc-San Dimas
 56,564 0 2.3 mi
Suburban Water Systems-Covina Knolls
 1,451 0 2.7 mi
Covina-City, Water Dept.
Covina		 33,300 0 2.8 mi
Azusa Light and Water
 110,044 0 3.3 mi
Metropolitan Water Dist. of So. Cal.
 0 0 3.8 mi
Valencia Heights Water Co.
 7,775 0 4.2 mi
Calif State Polytechnical Univ Pomona
 2,668 2 4.7 mi
Three Valleys Mwd
 0 0 4.8 mi
LA Verne, City WD
La Verne		 31,334 0 5.4 mi
Valley County Water Dist.
 68,871 0 6.1 mi
Cal-Am Water Company Duarte
 24,767 0 6.3 mi
Suburban Water Systems-San Jose
 170,523 0 6.8 mi
Pomona City, Water Dept.
Pomona		 151,713 0 6.9 mi
Valley View Mutual Water Co.
 4,613 0 7.3 mi
Walnut Valley Water District
 100,941 0 7.8 mi
Gswc Claremont
 39,776 0 7.9 mi
Monrovia-City, Water Dept.
Monrovia		 37,931 0 8.5 mi
The River Community
 35 2 8.5 mi
Camp Williams-Resort Water
 80 0 8.6 mi
LA Puente Valley Cwd
 8,276 0 8.7 mi
Hemlock Mutual Water Co.
 686 2 8.8 mi
City of Industry Waterworks Systems
La Puente		 6,151 0 8.9 mi
Sterling Mutual Water Company
 198 2 9.4 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-Chantry Flats-A16 Water
 113 0 0
Usfs-Crystal Lake B-13 Water
 2,000 0 0
Usfs-Skyline Park / Mount Wilson A-4
 25 0 0
Henninger Flats
 50 0 0
Usfs-Red Box Station A-3
 25 0 0
Usfs-Chilao Main A-9
 50 0 0
Angeles Crest Christian Camp
 112 1 0
Millard Canyon Improvement Association
 42 1 0
Huttopia Paradise Springs
 302 1 0
Colby Ranch-United Methodist Camp
 180 0 0
Mount Kare Camp/kare Youth League
 59 0 0
Usfs-Big Pines V-2
 54 0 0
Mountain High East Ski Area
 150 0 0
Usfs-Jackson Lake V-4
 805 0 0
Usfs-Appletree Flats V-3
 25 0 0
Clear Creek Outdoor Education Center
 105 0 0
Camp Elk
 121 0 0
Usfs-Monte Cristo Camp T-4
 116 0 0
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
Usfs-Valyermo Ranger Station
 25 1 1
Saint Andrews Abbey
 210 1 1
Rancho Ybarra Christian Camp
 73 0 0
1000 Trails / Soledad Canyon Preserve
 812 1 0
Acton Four Square Church
 50 0 0
Acton-Agua Dulce Lds Church
 150 0 0
Angeles Shooting Ranges
 490 0 0
Acton la North KOA
 400 0 0
General Atomics Aeronautical Gray Butt
 405 0 0
Acton Conservation Camp #11
 90 4 0
Desert Aire Golf Course
 80 0 0
Los Angeles World Airports
 180 0 0
Vasquez Rocks County Park
 30 0 0
Antelope Valley Indian Museum State Park
 506 0 0
Ilead Agua Dulce Charter School
 450 1 1
Agua Dulce Women's Club
 50 0 0
Lockheed Martin Skunk Works
 135 0 0
Lang Ranch Shopping Center
 28 0 0
Wagon Wheel Plaza
 55 1 0
Agua Dulce Water System
 493 0 0
Agua Dulce Winery
 113 0 0
Northrop Grumman Corp.
 5,764 1 0
Living Springs Church
 50 0 0
Shepherd of the Hills
 80 0 0
LE Chene Restaurant Water System
 100 0 0
Lancaster National Soccer Center
Lancaster 		500 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.