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 |
|---|---|---|---|---|
|
Mammoth Town of Mammoth · Pinal County |
1,181 | 6 | 1 | |
|
Copper Mountain Ranch Cfd Maricopa · Pinal County |
1,071 | 4 | 0 | |
|
Adoc Florence Asp Florence · Pinal County |
1,001 | 8 | 4 | |
|
Outlets North Phoenix Maricopa · Maricopa County |
1,000 | 2 | 1 | |
|
Ehrenberg Improvement District Ehrenberg · La Paz County |
989 | 1 | 0 | |
|
Chinle High School Chinle High School · County |
975 | 4 | 2 | |
|
Usdj Fbp Fed Corr Inst Safford Safford · Graham County |
949 | 5 | 0 | |
|
Maricopa Consolidated Dwid Maricopa · Pinal County |
928 | 4 | 1 | |
|
Metropolitan Dwid E&t System Tucson · Pima County |
880 | 2 | 0 | |
|
Tsehootsooi Middle School Fort Defiance · County |
875 | 5 | 1 | |
|
Verde Lakes Water Dinky Creek Camp Verde · Yavapai County |
875 | 6 | 0 | |
|
Verde Lakes Water Big Valley Camp Verde · Yavapai County |
870 | 6 | 1 | |
|
Heber Dwid Heber · Navajo County |
839 | 5 | 2 | |
|
Pinal County Justice Complex Florence · Pinal County |
820 | 6 | 2 | |
|
Patagonia Water Department Patagonia · Santa Cruz County |
819 | 1 | 0 | |
|
Adoc Aspc Fort Grant Bonita · Graham County |
800 | 7 | 1 | |
|
Willow Beach Nps Willow Beach · Mohave County |
789 | 8 | 2 | |
|
Liberty Elementary School Buckeye · Maricopa County |
775 | 5 | 0 | |
|
Rock Point Community School Bia Rock Point · County |
758 | 3 | 1 | |
|
Organ Pipe NM Headquarters Organ Pipe Nm · Pima County |
755 | 3 | 0 | |
|
Greasewood Springs Community Boarding School Bia Lower Greasewood · County |
720 | 7 | 3 | |
|
Havasu Springs Resort Parker · La Paz County |
708 | 2 | 0 | |
|
Scua Lower Peridot County |
702 | 7 | 3 | |
|
Adaman Mutual Water Company Adaman · Maricopa County |
700 | 8 | 1 | |
|
City of Hope Phoenix Goodyear · Maricopa County |
700 | 3 | 0 | |
|
Shonto Preparatory Boarding School Bia Shonto · County |
664 | 2 | 0 | |
|
CS Oak Creek Public Service LLC Cornville · Yavapai County |
650 | 4 | 0 | |
|
Kingman Stopping Center Kingman · Mohave County |
650 | 7 | 0 | |
|
San Carlos High School San Carlos High School · County |
626 | 5 | 0 | |
|
Dishchii Bikoh Community School Bia Charter County |
622 | 2 | 0 | |
|
Sipaulovi (lower Sipaulovi/lower Mishongnovi) Lower Sipaulovi, Lower Mishongnovi · County |
609 | 5 | 2 | |
|
Inscription Canyon Water Company Chino Valley · Yavapai County |
607 | 3 | 0 | |
|
Duncan Town of Duncan · Greenlee County |
605 | 6 | 0 | |
|
Ponderosa Park Dwid Prescott · Yavapai County |
602 | 5 | 1 | |
|
Appaloosa Water Company Chino Valley · Yavapai County |
600 | 5 | 2 | |
|
Sun Valley Farms Unit VI Queen Creek · Pinal County |
600 | 7 | 2 | |
|
St Michael Indian School St. Michaels · County |
585 | 5 | 1 | |
|
Glen Canyon Nra Wahweap Page · Coconino County |
579 | 6 | 0 | |
|
Scua Cutter County |
574 | 5 | 2 | |
|
Horizon Six Dwid Lake Havasu City · Mohave County |
560 | 3 | 0 | |
|
Navajo County Government Complex Holbrook · Navajo County |
540 | 4 | 0 | |
|
Hayden Town of Hayden · Gila County |
517 | 6 | 2 | |
|
SO HI Dwid Kingman · Mohave County |
513 | 3 | 1 | |
|
Bradshaw Water Company INC Prescott · Yavapai County |
510 | 4 | 1 | |
|
Lukachukai Community School New Lukachukai Community School New · County |
500 | 4 | 1 | |
|
Pinon Community Dormitory School Bia Pinon · County |
500 | 2 | 0 | |
|
Silver Bell Army Heliport Marana · Pinal County |
500 | 2 | 0 | |
|
Tacna Water Improvement District Tacna · Yuma County |
500 | 3 | 0 | |
|
CS Christopher Creek Haven Christopher Creek · Gila County |
497 | 3 | 0 | |
|
Mishongnovi (upper Sipaulovi/upper Mishongnovi) Upper Sipaulovi, Upper Mishongnovi · County |
490 | 4 | 1 |
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.