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 |
|---|---|---|---|---|
|
G & L Mobile Park Yuma · Yuma County |
90 | 6 | 1 | |
|
Tonto Basin School District 33 Punkin Center · Gila County |
90 | 6 | 2 | |
|
Six Mile and Steamboat Village Six Mile And Steamboat Village · County |
88 | 4 | 0 | |
|
Navajo County Public Works Complex Holbrook · Navajo County |
86 | 5 | 1 | |
|
Usfs Knf Tusayan Admin Tusayan · Coconino County |
80 | 6 | 1 | |
|
Metropolitan Dwid Lazy B Tucson · Pima County |
77 | 2 | 0 | |
|
Beaver Dam WC System 3 Littlefield · Mohave County |
75 | 5 | 0 | |
|
Majestic View Water Improvement District Fort Valley · Coconino County |
70 | 8 | 2 | |
|
McNeal Water Company Mcneal · Cochise County |
66 | 6 | 0 | |
|
Buckeye Armed Forces Reserve Center Buckeye · Maricopa County |
63 | 3 | 0 | |
|
Crisantes Greenhouse Water System Amado · Santa Cruz County |
60 | 6 | 1 | |
|
Montezuma Heights Water Camp Verde · Yavapai County |
60 | 2 | 0 | |
|
Rio Vista Ranches Mohave Valley · Mohave County |
59 | 6 | 0 | |
|
Katherine Resorts Water Company Bullhead City · Mohave County |
58 | 7 | 0 | |
|
Rancho Sierrita Well Assoc Tucson · Pima County |
51 | 3 | 2 | |
|
Gunsight (schuchuligk) Schuchuligk · County |
40 | 2 | 1 | |
|
CS Old Concho Water Users Concho · Apache County |
40 | 7 | 0 | |
|
Westside Industrial Investments LLC Glendale · Maricopa County |
30 | 4 | 2 |
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.