Tapcensus

California

Los Angeles County drinking water quality

271 active public water systems serve 10,081,756 people in Los Angeles County. 205 are compliant, 66 had at least one EPA violation in the past three years, 4 are designated serious violators, and 24 carry a health flag.

Active systems 271 199 community systems
People served 10.1M by public water systems
Systems with violations 66 24% of active systems, past 3 years
Serious violators 4 24 systems carry a health flag

Needs attention

Calif State Polytechnical Univ Pomona CA1910022 · Community water system · Serves 2,668 2 rules violated in the past three years. Unresolved: Lead and Copper Rule Revisions.
Alpine Springs Mobile Home Park CA1900942 · Community water system · Serves 175 2 rules violated in the past three years. Unresolved: Lead and Copper Rule and Lead and Copper Rule Revisions.
Mescal Creek Water, INC CA1900147 · Community water system · Serves 80 2 rules violated in the past three years. Unresolved: Surface Water Treatment Rule and Stage 1 Disinfectants and Disinfection Byproducts Rule.
Rivers End Trailer Park CA1900868 · Community water system · Serves 35 2 rules violated in the past three years. Unresolved: Lead and Copper Rule and Lead and Copper Rule Revisions.
Monterey Park-City, Water Dept. CA1910092 · Monterey Park · Community water system · Serves 61,096 1 rule violated in the past three years. Unresolved: Lead and Copper Rule Revisions.
Green Valley Cwd CA1910244 · Community water system · Serves 1,275 1 rule violated in the past three years. Unresolved: Lead and Copper Rule Revisions.
Del Rio Mutual CA1900130 · Community water system · Serves 700 1 rule violated in the past three years. Unresolved: Lead and Copper Rule Revisions.
Hemlock Mutual Water Co. CA1910053 · Community water system · Serves 686 2 rules violated in the past three years. Unresolved: Lead and Copper Rule Revisions.
Eastside Union School District CA1900751 · Non-Transient non-community system · Serves 650 1 rule violated in the past three years. Unresolved: Lead and Copper Rule Revisions.
Llano del Rio Water Company CA1900849 · Community water system · Serves 545 1 rule violated in the past three years. Unresolved: Lead and Copper Rule Revisions.

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

Community water systems

199 systems, largest first
SystemServesStatusRules violated, 3 yrUnresolved
Maywood Mutual Water Co. #3
 6,059 0 0
Bellflower Municipal Water System
 6,032 0 0
LA Habra Heights Cwd
 5,682 0 0
Palm Ranch Irrigation Dist.
 5,507 0 0
Suburban Water Systems-Glendora
 5,301 0 0
San Gabriel Valley Water Co-Montebello 1
 5,205 0 0
Los Angeles Cwwd 37-Acton
 4,782 0 0
Valley View Mutual Water Co.
 4,613 0 0
Suburban Water Systems Sativa
 4,372 0 0
Maywood Mutual Water Co. #1
 3,851 0 0
So. Cal. Edison Co.-Santa Catalina
 3,822 0 0
San Gabriel Valley Water Co-Montebello 2
Montebello 		3,731 0 0
Commerce-City, Water Dept.
Montebello 		3,598 0 0
Amarillo Mutual Water Company
 3,134 0 0
Littlerock Creek Irrigation Dist.
 3,066 1 0
Land Projects Mutual Water Co.
 2,800 1 0
Calif State Polytechnical Univ Pomona
 2,668 2 1
Las Flores Water Co.
 2,211 0 0
Kinneloa Irrigation Dist.
 1,808 1 0
Lake Elizabeth Mutual Water Co.
 1,790 0 0
Liberty Utilities Mesa Crest
 1,616 0 0
Lynwood Park Mutual Water Co.
 1,564 1 1
White Fence Farms Mwc No. 1
 1,518 0 0
Suburban Water Systems-Covina Knolls
 1,451 0 0
California Water Service Co.-Lancaster
 1,416 0 0
Green Valley Cwd
 1,275 1 1
Sundale Mutual Water Company A, B
 1,155 0 0
Bellflower Home Garden Water Company
 1,129 1 1
Los Angeles Cwwd 40, Reg. 39-Rock Creek
 1,030 0 0
Averydale Mwc
 1,026 1 0
California Water Service Co-Leona Valley
 895 0 0
West Valley County Water District
 798 0 0
Los Angeles Cwwd 40, Reg. 35-N.e. L.a.
 792 0 0
White Fence Farms Mwc No.3
 749 0 0
Los Angeles Cwwd 21-Kagel Canyon
 736 0 0
California Water Service Co-Lake Hughes
 732 0 0
Del Rio Mutual
 700 1 1
Hemlock Mutual Water Co.
 686 2 1
EL Dorado Mutual Water Co.
 660 0 0
Lily of the Valley Mobile Village
 657 0 0
Llano del Rio Water Company
 545 1 1
Sherwood Mobile Home Park
 540 0 0
Westside Park Mutual Water
 495 0 0
Golden Sands Mobile Home Park
 450 1 1
Shadow Acres Mutual Water Company
 450 0 0
Antelope Park Mutual Water Company
 445 0 0
Sunnyside Farms Mutual Water Company
 436 3 1
Californian Mobile Home Park
 414 0 0
Paradise Ranch MHP
 360 0 0
Leisure Lake Mobile Estates
 325 1 1
Non-community systems (72: schools, campgrounds, workplaces, restaurants)

These systems serve places people visit rather than homes.

SystemServesStatusRules violated, 3 yrUnresolved
Antelope Valley Poppy Reserve State Park
 25,007 0 0
Northrop Grumman Corp.
 5,764 1 0
Rancho los Amigos Hospital
 3,200 0 0
Flying J Travel Center
 2,565 0 0
Usfs-Crystal Lake B-13 Water
 2,000 0 0
Camp Verdugo Oaks Boyscouts
 1,500 0 0
Del Sur School/westside Union District
 825 1 0
1000 Trails / Soledad Canyon Preserve
 812 1 0
Usfs-Jackson Lake V-4
 805 0 0
Eastside Union School District
 650 1 1
Hughes-Elizabeth Lake Unified School Dis
 550 2 1
Antelope Valley Indian Museum State Park
 506 0 0
Lancaster National Soccer Center
Lancaster 		500 0 0
Mira Loma High Desert Hospital
 500 0 0
Agua Dulce Water System
 493 0 0
Angeles Shooting Ranges
 490 0 0
Ilead Agua Dulce Charter School
 450 1 1
General Atomics Aeronautical Gray Butt
 405 0 0
Acton la North KOA
 400 0 0
Huttopia Paradise Springs
 302 1 0
Irwindale Brewery Yard (iby)
 300 0 0
Saint Andrews Abbey
 210 1 1
Anchor Retreat Center
 202 0 0
Usfs-Buckhorn Camp A-12 Water
 185 0 0
Colby Ranch-United Methodist Camp
 180 0 0
Los Angeles World Airports
 180 0 0
Canyon Creek Outdoor Education Center
 177 0 0
Acton-Agua Dulce Lds Church
 150 0 0
Mountain High East Ski Area
 150 0 0
Dwr. Vista del Lago Visitor Ctr,vaquerro
 135 0 0
Lockheed Martin Skunk Works
 135 0 0
Quail Canyon Sea
 130 0 0
Camp Elk
 121 0 0
Usfs-Monte Cristo Camp T-4
 116 0 0
Agua Dulce Winery
 113 0 0
Usfs-Chantry Flats-A16 Water
 113 0 0
Angeles Crest Christian Camp
 112 1 0
Halfway House Cafe
 112 1 0
Clear Creek Outdoor Education Center
 105 0 0
LE Chene Restaurant Water System
 100 0 0
Acton Conservation Camp #11
 90 4 0
Desert Aire Golf Course
 80 0 0
Shepherd of the Hills
 80 0 0
Rancho Ybarra Christian Camp
 73 0 0
The Oaks
 67 0 0
Tarzana Treatment Centers, Inc.
 60 0 0
Mount Kare Camp/kare Youth League
 59 0 0
Los Angeles, City of Castaic Pwr Plant
 55 0 0
Wagon Wheel Plaza
 55 1 0
Usfs-Big Pines V-2
 54 0 0
Martin Marietta Southern Calif Aggregate
 51 0 0
Acton Four Square Church
 50 0 0
Agua Dulce Women's Club
 50 0 0
Henninger Flats
 50 0 0
Living Springs Church
 50 0 0
Usfs-Chilao Main A-9
 50 0 0
Plant Water Well Rockview Dairy
South Gate 		45 0 0
Millard Canyon Improvement Association
 42 1 0
Coldbrook Campground
 38 0 0
TN Truss
 35 1 0
Texas Canyon Ranger Station
 30 0 0
Usfs-Pyramid Lake S-14
 30 0 0
Vasquez Rocks County Park
 30 0 0
Lang Ranch Shopping Center
 28 0 0
Pyramid Lake RV Resort
 26 1 0
Kirk Business Center
 25 0 0
Usfs-Appletree Flats V-3
 25 0 0
Usfs-Los Alamos S-15
 25 0 0
Usfs-Red Box Station A-3
 25 0 0
Usfs-Skyline Park / Mount Wilson A-4
 25 0 0
Usfs-Valyermo Ranger Station
 25 1 1
Young-Nak Presbyterian Church
 25 0 0
Inactive systems (355, 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.