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 |
|---|---|---|---|---|
|
Porter Mountain Dwid Lakeside · Navajo County |
322 | 6 | 2 | |
|
Nps Temple Bar Wtp Temple Bar · Mohave County |
305 | 4 | 0 | |
|
Tucson Electric Power Springerville · Apache County |
300 | 1 | 0 | |
|
Valle Verde del Norte Green Valley · Pima County |
300 | 4 | 1 | |
|
MT Lemmon Dwid Mount Lemmon · Pima County |
290 | 2 | 1 | |
|
Sun Valley Utilities Sun Valley · Navajo County |
287 | 8 | 3 | |
|
Villa Grande Dwid Eloy · Pinal County |
283 | 7 | 0 | |
|
Ghr Landowners Assn Water Coop White Hills · Mohave County |
280 | 7 | 2 | |
|
LA Casita Water Company 2 Tucson · Pima County |
264 | 2 | 1 | |
|
Thim Utility Company Well 9 Three Points · Pima County |
254 | 1 | 0 | |
|
Antelope Union High School Yuma · Yuma County |
250 | 8 | 0 | |
|
Porter Creek Dwid Lakeside · Navajo County |
250 | 7 | 4 | |
|
Seba Dalkai Boarding School Bia Seba Dalkai · County |
250 | 4 | 2 | |
|
Yucca Water Association Yucca · Mohave County |
250 | 4 | 1 | |
|
CS Mohawk Utility Company Tacna · Yuma County |
243 | 8 | 0 | |
|
Wmatua Carrizo Carrizo · County |
228 | 2 | 1 | |
|
Camp Mohave Bullhead City · Mohave County |
224 | 6 | 1 | |
|
Pinedale Estates Dwid Show Low · Navajo County |
208 | 6 | 1 | |
|
Aguila Elementary School Aguila · Maricopa County |
200 | 4 | 1 | |
|
Naturesweet USA Fort Grant · Graham County |
200 | 2 | 0 | |
|
Nissan Technical Center Stanfield · Pinal County |
200 | 2 | 0 | |
|
Silverbell Mining, LLC Marana · Pima County |
200 | 3 | 0 | |
|
Whispering Wind Mobile Home Park Coolidge · Pinal County |
200 | 4 | 1 | |
|
Seven Canyons of Sedona Sedona · Yavapai County |
195 | 4 | 2 | |
|
Snowbird RV Park Fort Mohave · Mohave County |
180 | 6 | 1 | |
|
CS Lake Verde Water Company Camp Verde · Yavapai County |
169 | 4 | 0 | |
|
CS Antelope Water Company Mohawk · Yuma County |
163 | 5 | 0 | |
|
Greenfields Country Day School Tucson · Pima County |
163 | 6 | 0 | |
|
Beaver Dam WC System 2 Mesquite City · Mohave County |
162 | 5 | 0 | |
|
Kaka Kaka · County |
150 | 3 | 1 | |
|
Usaf Gila Bend Gila Bend · Maricopa County |
150 | 4 | 0 | |
|
Kohls Ranch Water Company Kohls Ranch · Gila County |
141 | 9 | 2 | |
|
Canyon Water Improvement District Globe · Gila County |
130 | 3 | 0 | |
|
Bonita Public School Willcox · Graham County |
128 | 6 | 3 | |
|
Apache Lake Marina Resort Apache Lake · Maricopa County |
123 | 5 | 0 | |
|
Beverly Gardens Trailer Park Prescott · Yavapai County |
120 | 4 | 0 | |
|
Cowlic Cowlic · County |
120 | 1 | 0 | |
|
Turquoise Triangle RV Park Cottonwood · Yavapai County |
120 | 3 | 0 | |
|
Verde Glen Dwid Payson · Gila County |
117 | 7 | 3 | |
|
Sherman Pines Water Company Sherman Pines · Yavapai County |
110 | 3 | 0 | |
|
Cienega Water Company INC Parker · La Paz County |
108 | 8 | 2 | |
|
Catalina Village Tucson · Pima County |
107 | 3 | 1 | |
|
Bellemont Water Company Bellemont · Coconino County |
100 | 7 | 2 | |
|
Holbrook Sda Indian School Holbrook · Navajo County |
100 | 5 | 0 | |
|
Pine Water Association Dwid Pine · Gila County |
100 | 7 | 5 | |
|
Valley Union High School Elfrida · Cochise County |
100 | 4 | 0 | |
|
Yavapai Country Club Estates Water CO Peeples Valley · Yavapai County |
100 | 4 | 2 | |
|
Signal Peak Water Company Coolidge · Pinal County |
99 | 4 | 0 | |
|
Sahuarita Village Water Company Sahuarita · Pima County |
93 | 5 | 1 | |
|
Chimney Estates Mayer · Yavapai County |
90 | 6 | 1 |
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.