TTHM (Total Trihalomethanes) violations in Arizona
218 active public water systems in Arizona had a TTHM (Total Trihalomethanes) violation in the past three years, 23 of them in the latest quarter of EPA's data. What TTHM (Total Trihalomethanes) is and why it matters.
Systems with a TTHM (Total Trihalomethanes) violation
Latest quarter first, then largest first| System | Serves | Status | Rules violated, 3 yr | Unresolved |
|---|---|---|---|---|
|
Elfrida Wid Elfrida · Cochise County |
800 | 6 | 0 | |
|
Willow Beach Nps Willow Beach · Mohave County |
789 | 8 | 2 | |
|
Cottonwood Municipal Water VV 1 Camp Verde · Yavapai County |
783 | 1 | 0 | |
|
Lake Mohave Highlands Bullhead City · Mohave County |
746 | 6 | 0 | |
|
Marana Dwid Culver Marana · Pima County |
709 | 4 | 1 | |
|
City of Hope Phoenix Goodyear · Maricopa County |
700 | 3 | 0 | |
|
Papago Butte Dwid Maricopa · Pinal County |
700 | 4 | 1 | |
|
Pinto Valley Mine Globe · Gila County |
699 | 3 | 0 | |
|
Kingman Stopping Center Kingman · Mohave County |
650 | 7 | 0 | |
|
San Carlos High School San Carlos High School · County |
626 | 5 | 0 | |
|
Ponderosa Park Dwid Prescott · Yavapai County |
602 | 5 | 1 | |
|
Appaloosa Water Company Chino Valley · Yavapai County |
600 | 5 | 2 | |
|
LA Casita Water Company 3 Tucson · Pima County |
598 | 2 | 0 | |
|
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 | |
|
Anway Manville Water Company Avra Valley · Pima County |
550 | 2 | 1 | |
|
Aspc Apache Winslow · Apache County |
540 | 5 | 0 | |
|
Navajo County Government Complex Holbrook · Navajo County |
540 | 4 | 0 | |
|
Inscription Canyon Water Company Prescott · Yavapai County |
532 | 4 | 0 | |
|
Hayden Town of Hayden · Gila County |
517 | 6 | 2 | |
|
Tonto Basin Water Roosevelt Lake Estates Payson · Gila County |
508 | 2 | 0 | |
|
Lower Moencopi Spring Source Lower Moencopi · County |
465 | 12 | 3 | |
|
Bowie Wid Bowie · Cochise County |
453 | 3 | 0 | |
|
Douglas Border Patrol Station Douglas · Cochise County |
450 | 3 | 0 | |
|
Highland Pine Dwid Prescott · Yavapai County |
450 | 4 | 0 | |
|
Thim Utility Company 2 Tucson · Pima County |
445 | 1 | 0 | |
|
Montezuma Rimrock Water Company Rimrock · Yavapai County |
439 | 1 | 0 | |
|
Grand Canyon Junction Hydro Valle · Coconino County |
430 | 6 | 0 | |
|
Shepard Water Company Martinez Lake · Yuma County |
430 | 7 | 2 | |
|
Clay Springs Dwid Clay Springs · Navajo County |
425 | 2 | 0 | |
|
Reliance Jrc Goodyear Litchfield Park · Maricopa County |
425 | 1 | 0 | |
|
Asarco Hayden Operations Hayden · Gila County |
417 | 5 | 0 | |
|
Katherine Heights Bullhead City · Mohave County |
415 | 7 | 0 | |
|
Ajo Dwid Ajo · Pima County |
405 | 2 | 0 | |
|
Valle Escondido Maricopa · Pinal County |
405 | 7 | 0 | |
|
Fishers Landing Resort Yuma · Yuma County |
402 | 3 | 0 | |
|
Eden Water Company INC Safford · Graham County |
400 | 6 | 0 | |
|
Marana Aerospace Solutions Marana · Pinal County |
400 | 4 | 0 | |
|
Picacho Peak RV Resort Red Rock · Pinal County |
400 | 6 | 1 | |
|
Granite Mountain Water Company Prescott · Yavapai County |
381 | 5 | 3 | |
|
Wonderland Acres Dwid Lakeside · Navajo County |
380 | 8 | 4 | |
|
Desert Diamond Why County |
362 | 1 | 0 | |
|
Chloride Dwid Chloride · Mohave County |
350 | 2 | 0 | |
|
Federal Correctional Inst Tucson · Pima County |
350 | 9 | 0 | |
|
Gowan Milling LLC Yuma · Yuma County |
350 | 7 | 1 | |
|
Timberline MHP Show Low · Navajo County |
350 | 5 | 2 | |
|
Low Mountain Boarding School Bia Low Mountain · County |
339 | 3 | 2 | |
|
Lower Moencopi Consecutive System Lower Moencopi · County |
326 | 6 | 3 |
About this data
A system is counted once if any of its violations in the past three years involved TTHM (Total Trihalomethanes), including monitoring and reporting lapses. Rules violated and status in the table are for the whole system, not TTHM (Total Trihalomethanes) 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.