TTHM (Total Trihalomethanes) violations in Alaska
119 active public water systems in Alaska 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 |
|---|---|---|---|---|
|
Kobuk Water System Kobuk · Northwest Arctic Borough County |
93 | 8 | 1 | |
|
Akhiok Akhiok · Kodiak Island Borough County |
90 | 9 | 0 | |
|
Perryville Water System Perryville · Lake and Peninsula Borough County |
88 | 11 | 0 | |
|
Koyukuk Safewater Facility Koyukuk · Yukon-Koyukuk Census Area County |
85 | 6 | 1 | |
|
Beaver Water System Beaver · Yukon-Koyukuk Census Area County |
80 | 6 | 0 | |
|
Lksd Kipnuk HS Kipnuk · Bethel Census Area County |
80 | 7 | 2 | |
|
Lksd Napakiak HS & Elem Napakiak · Bethel Census Area County |
80 | 6 | 1 | |
|
Chalkyitsik Village Water Chalkyitsik · Yukon-Koyukuk Census Area County |
76 | 7 | 2 | |
|
Alaska Christian College Soldotna · Kenai Peninsula Borough County |
70 | 3 | 0 | |
|
Takotna Water System Takotna · Yukon-Koyukuk Census Area County |
70 | 7 | 1 | |
|
Lksd Mekoryuk Nunivaarmiut SC Mekoryuk · Bethel Census Area County |
67 | 6 | 0 | |
|
Kasaan Ketchikan · Ketchikan Gateway Borough County |
66 | 3 | 0 | |
|
Nelson Lagoon Water System Nelson Lagoon · Aleutians East Borough County |
60 | 8 | 0 | |
|
Shageluk Water System Shageluk · Yukon-Koyukuk Census Area County |
60 | 8 | 1 | |
|
Chenega Chenega Bay · County |
50 | 5 | 0 | |
|
Southeast Alaska Logging Kodiak · Kodiak Island Borough County |
45 | 6 | 0 | |
|
Stevens Village Water System Stevens Village · Yukon-Koyukuk Census Area County |
28 | 6 | 2 | |
|
Faa Bethel Well Bethel · Bethel Census Area County |
25 | 6 | 1 | |
|
Ketchikan H2o Ketchikan · Ketchikan Gateway Borough County |
25 | 2 | 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 Alaska 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.