Chlorine (MRDL) violations in Arizona
274 active public water systems in Arizona had a Chlorine (MRDL) violation in the past three years, 24 of them in the latest quarter of EPA's data. What Chlorine (MRDL) is and why it matters.
Health effects: Acute high-dose exposure to chlorinated water can cause eye and nose irritation, stomach discomfort, and nausea. Chronic exposure above the MRDL is primarily a concern because elevated chlorine accelerates formation of trihalomethanes and haloacetic acids, which are associated with increased cancer risk over time.
Systems with a Chlorine (MRDL) violation
Latest quarter first, then largest first| System | Serves | Status | Rules violated, 3 yr | Unresolved |
|---|---|---|---|---|
|
GW Farmers Water CO Continental Green Valley · Pima County |
4,475 | 1 | 0 | |
|
Aspc Yuma Yuma · Yuma County |
4,197 | 4 | 0 | |
|
Town of Taylor Taylor · Navajo County |
4,190 | 7 | 2 | |
|
Polacca First Mesa Consolidated Villages · County |
3,890 | 6 | 4 | |
|
Spanish Trail Water Company Tucson · Pima County |
3,822 | 3 | 0 | |
|
Carefree Water Company Carefree · Maricopa County |
3,588 | 3 | 0 | |
|
ST Johns City of Saint Johns · Apache County |
3,500 | 5 | 1 | |
|
Colorado River Regional Water System County |
3,476 | 6 | 0 | |
|
Arizona Village County |
3,211 | 10 | 2 | |
|
Scua Bylas Bylas · County |
3,160 | 12 | 3 | |
|
Williams City of Williams · Coconino County |
3,145 | 7 | 1 | |
|
Tucson Medical Center Tucson · Pima County |
3,000 | 4 | 1 | |
|
Wellton Town of Wellton · Yuma County |
3,000 | 10 | 1 | |
|
Hondah Casino County |
2,926 | 6 | 1 | |
|
Quartzsite Town of Quartzsite · La Paz County |
2,761 | 2 | 0 | |
|
Chino Valley Town of Chino Valley · Yavapai County |
2,742 | 4 | 0 | |
|
Goodman Water Company Catalina · Pinal County |
2,668 | 2 | 0 | |
|
Chandler Heights Citrus Irrigation Dist Chandler · Maricopa County |
2,620 | 3 | 1 | |
|
Tonto Apache County |
2,580 | 6 | 1 | |
|
Foothills Utilities Kingman East Kingman · Mohave County |
2,538 | 4 | 0 | |
|
Black Canyon City Wid Black Canyon City · Yavapai County |
2,437 | 6 | 1 | |
|
Ash Fork Water Service Ash Fork · Yavapai County |
2,350 | 2 | 0 | |
|
Chino Meadows II Chino Valley · Yavapai County |
2,350 | 6 | 4 | |
|
Bia San Carlos County |
2,150 | 8 | 1 | |
|
San Carlos Apache Health Center County |
2,085 | 3 | 0 | |
|
Tuba City Boarding School Bia Tuba City Bia Boarding School · County |
2,040 | 2 | 0 | |
|
Voyager at White Mountain Lakes WC White Mountain Lakes · Navajo County |
1,997 | 4 | 1 | |
|
Abra Water Company Paulden · Yavapai County |
1,932 | 4 | 0 | |
|
Gila Bend Town of Buckeye · Maricopa County |
1,922 | 7 | 0 | |
|
Congress Dwid Congress · Yavapai County |
1,870 | 2 | 0 | |
|
Joseph City Dwid Joseph City · Navajo County |
1,811 | 4 | 1 | |
|
Camp Verde School Dist 28 Camp Verde · Yavapai County |
1,810 | 4 | 3 | |
|
CS Harrisburg Utility Company Salome · La Paz County |
1,759 | 4 | 0 | |
|
Petrified Forest NP Holbrook · Apache County |
1,742 | 5 | 0 | |
|
Upper Moenkopi Upper Moenkopi · County |
1,740 | 2 | 0 | |
|
CS Hydro Resources-Tusayan Tusayan · Coconino County |
1,710 | 4 | 0 | |
|
Bisbee Douglas Intl Airport Bisbee · Cochise County |
1,700 | 3 | 1 | |
|
Morenci Water Elec CO Clifton Clifton · Greenlee County |
1,680 | 2 | 0 | |
|
Hotevilla Village Hotevilla, Hotevilla/bacavi Community Sc · County |
1,601 | 8 | 4 | |
|
Lagoon Estates WC Unit 7 Fort Mohave · Mohave County |
1,578 | 2 | 0 | |
|
Brophy College Preparatory Phoenix · Maricopa County |
1,500 | 3 | 1 | |
|
Federal Correction Institution Phoenix · Maricopa County |
1,500 | 5 | 0 | |
|
Shungopavi Shungopavi · County |
1,430 | 7 | 3 | |
|
Bearizona Williams · Coconino County |
1,423 | 6 | 0 | |
|
Mayer Dwid Mayer · Yavapai County |
1,400 | 7 | 1 | |
|
Kayenta Sandstone Housing Kayenta · County |
1,375 | 5 | 1 | |
|
Fredonia Town of Fredonia · Coconino County |
1,327 | 5 | 1 | |
|
Katherine Landing Dwtp Katherine Landing · Mohave County |
1,300 | 5 | 0 | |
|
Cameron Trading Post Cameron · Coconino County |
1,270 | 8 | 1 | |
|
Granite Oaks Water Users Association Prescott · Yavapai County |
1,200 | 5 | 3 |
About this data
A system is counted once if any of its violations in the past three years involved Chlorine (MRDL), including monitoring and reporting lapses. Rules violated and status in the table are for the whole system, not Chlorine (MRDL) alone.
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 Arizona 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.