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 |
|---|---|---|---|---|
|
Nogales City of Nogales · Santa Cruz County |
22,000 | 7 | 0 | |
|
Ponderosa Dwid Pinetop · Navajo County |
5,375 | 3 | 0 | |
|
Pinetop Water Community Facilities Dist Pinetop · Navajo County |
3,250 | 3 | 0 | |
|
City of Willcox Willcox · Cochise County |
3,236 | 6 | 0 | |
|
Freeport McMoran Bagdad Town Bagdad · Yavapai County |
3,200 | 2 | 0 | |
|
Jbs Tolleson Tolleson · Maricopa County |
1,700 | 2 | 0 | |
|
White Mountain Summer Homes Dwid Pinetop · Navajo County |
1,233 | 7 | 1 | |
|
Hopi High School Bia Hopi High School · County |
1,005 | 11 | 4 | |
|
Town & Country Preston Nogales · Santa Cruz County |
430 | 6 | 5 | |
|
Wonderland Acres Dwid Lakeside · Navajo County |
380 | 8 | 4 | |
|
Porter Mountain Dwid Lakeside · Navajo County |
322 | 6 | 2 | |
|
San Simon Dwid San Simon · Cochise County |
312 | 6 | 2 | |
|
Bouse Dwid Bouse · La Paz County |
284 | 7 | 1 | |
|
Second Mesa Day School Bia County |
255 | 6 | 1 | |
|
Porter Creek Dwid Lakeside · Navajo County |
250 | 7 | 4 | |
|
Kino Ranch 2 Nogales · Santa Cruz County |
173 | 4 | 0 | |
|
Ellison Creek Cabin Owners' Association Payson · Gila County |
159 | 4 | 2 | |
|
Monte Vista Water Company Douglas · Cochise County |
150 | 8 | 1 | |
|
Usaf Gila Bend Gila Bend · Maricopa County |
150 | 4 | 0 | |
|
Bonita Public School Willcox · Graham County |
128 | 6 | 3 | |
|
Freeport McMoran Bagdad Big Sandy Cyprus Bagdad · Yavapai County |
110 | 2 | 0 | |
|
Holbrook Sda Indian School Holbrook · Navajo County |
100 | 5 | 0 | |
|
Majestic View Water Improvement District Fort Valley · Coconino County |
70 | 8 | 2 | |
|
Avondale City of Avondale · Maricopa County |
96,130 | 2 | 0 | |
|
Epcor San Tan Johnson Ranch · Pinal County |
87,435 | 3 | 0 | |
|
GW Santa Cruz Water CO Maricopa · Pinal County |
84,000 | 7 | 0 | |
|
Kingman Municipal Water Kingman · Mohave County |
45,000 | 2 | 0 | |
|
EL Mirage City of El Mirage · Maricopa County |
39,884 | 4 | 0 | |
|
Bullhead City Mohave Bullhead City · Mohave County |
36,330 | 13 | 1 | |
|
City of Buckeye Valencia Town Division Buckeye · Maricopa County |
30,377 | 3 | 1 | |
|
Pima Utilities Chandler · Maricopa County |
20,000 | 7 | 3 | |
|
Douglas City of Douglas · Cochise County |
16,656 | 2 | 0 | |
|
Grand Canyon National Park Grand Canyon · Coconino County |
16,590 | 7 | 0 | |
|
US Army Fort Huachuca Fort Huachuca · Cochise County |
15,603 | 2 | 0 | |
|
Marana Municipal Marana Marana · Pima County |
15,162 | 1 | 0 | |
|
Beardsley Water Company 1 Surprise · Maricopa County |
10,881 | 1 | 0 | |
|
Epcor San Tan Anthem Johnson Ranch · Pinal County |
10,362 | 2 | 0 | |
|
City of Buckeye Tartesso Water System Buckeye · Maricopa County |
10,123 | 2 | 0 | |
|
Tolleson City of Tolleson · Maricopa County |
9,300 | 4 | 0 | |
|
Eloy City of Eloy · Pinal County |
8,999 | 6 | 1 | |
|
Scua Upper Seven Mile County |
8,478 | 12 | 3 | |
|
Avra Water Coop INC Tucson · Pima County |
6,685 | 2 | 0 | |
|
Wickenburg Town of Wickenburg · Maricopa County |
6,581 | 2 | 0 | |
|
Sunrise Water Company Peoria · Maricopa County |
6,500 | 1 | 0 | |
|
Valley Pioneers Water Company INC Kingman · Mohave County |
6,263 | 4 | 0 | |
|
Rose Valley Water Company Phoenix · Maricopa County |
6,202 | 1 | 0 | |
|
Epcor Rio Verde Rio Verde · Maricopa County |
5,330 | 2 | 0 | |
|
Holbrook City of Holbrook · Navajo County |
4,833 | 6 | 2 | |
|
Epcor Lake Havasu Lake Havasu City · Mohave County |
4,712 | 5 | 0 | |
|
Eagar Town of Eagar · Apache County |
4,590 | 5 | 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.