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.
Health effects: Long-term exposure is associated with increased bladder cancer risk. Some studies link high TTHM exposure to adverse reproductive outcomes. Bromodichloromethane is classified as a possible human carcinogen.
Systems with a TTHM (Total Trihalomethanes) violation
Latest quarter first, then largest first| System | Serves | Status | Rules violated, 3 yr | Unresolved |
|---|---|---|---|---|
|
Kivalina Water System Kivalina · Northwest Arctic Borough County |
452 | 7 | 0 | |
|
Brevig Mission Water System Brevig Mission · Nome Census Area County |
442 | 5 | 0 | |
|
Hydaburg Hydaburg · County |
415 | 10 | 3 | |
|
Kake Municipal Water Kake · County |
415 | 4 | 0 | |
|
Kwigillingok Washeteria Kwigillingok · Bethel Census Area County |
400 | 10 | 0 | |
|
Lksd Tununak Paul Albert HS Tununak · Bethel Census Area County |
385 | 9 | 0 | |
|
Saint Paul Water System Saint Paul · Aleutians West Census Area County |
380 | 7 | 1 | |
|
Tuluksak Water System Tuluksak · Bethel Census Area County |
373 | 9 | 0 | |
|
Nikolaevsk Community Water System Nikolaevsk · Kenai Peninsula Borough County |
360 | 6 | 0 | |
|
Akiak Community Water System Akiak · Bethel Census Area County |
346 | 6 | 0 | |
|
McGrath Water System Mcgrath · Yukon-Koyukuk Census Area County |
341 | 5 | 0 | |
|
Atmautluak Water System Atmautluak · Bethel Census Area County |
311 | 8 | 1 | |
|
Marshall Water System Marshall · County |
308 | 8 | 0 | |
|
Milne Point Unit Hilcorp Prudhoe Bay · North Slope Borough County |
300 | 2 | 0 | |
|
Quality Services, LLC Water Delivery Nome · Nome Census Area County |
300 | 3 | 1 | |
|
Nanwalek Nanwalek · Kenai Peninsula Borough County |
281 | 11 | 2 | |
|
Eek Water System Eek · Bethel Census Area County |
280 | 9 | 0 | |
|
Larsen Bay Water System Larsen Bay · Kodiak Island Borough County |
271 | 11 | 0 | |
|
Too'gha INC in Tanana Tanana · Yukon-Koyukuk Census Area County |
271 | 9 | 1 | |
|
Shaktoolik Water System Shaktoolik · Nome Census Area County |
270 | 6 | 0 | |
|
Prudhoe Bay Hotel Prudhoe Bay · North Slope Borough County |
260 | 1 | 0 | |
|
Old Harbor Old Harbor · Kodiak Island Borough County |
246 | 9 | 0 | |
|
Old Kasigluk Akiuk Kasigluk · Bethel Census Area County |
240 | 7 | 1 | |
|
Nsbu Point Lay Pt. Lay · North Slope Borough County |
237 | 4 | 0 | |
|
Vallenar View Mobile Home Park Ketchikan · Ketchikan Gateway Borough County |
225 | 3 | 0 | |
|
Northway Washeteria Northway · Southeast Fairbanks Census Area County |
223 | 1 | 0 | |
|
Kivalina K-12 School Kivalina · Northwest Arctic Borough County |
217 | 5 | 0 | |
|
Nunam Iqua Water System Nunam Iqua · Bethel Census Area County |
213 | 11 | 1 | |
|
Grayling Water System Grayling · Yukon-Koyukuk Census Area County |
207 | 13 | 2 | |
|
Minto Community Water System Minto · Yukon-Koyukuk Census Area County |
205 | 10 | 0 | |
|
Nondalton Nondalton · Lake and Peninsula Borough County |
205 | 10 | 2 | |
|
Napaskiak West Water System Napaskiak · Bethel Census Area County |
200 | 8 | 1 | |
|
Chignik Bay Water System Chignik Bay · Lake and Peninsula Borough County |
199 | 6 | 1 | |
|
Creekwood Park Water System Wasilla · Matanuska-Susitna Borough County |
192 | 6 | 0 | |
|
Venetie Water System Venetie · Yukon-Koyukuk Census Area County |
181 | 7 | 1 | |
|
Port Graham Port Graham · Kenai Peninsula Borough County |
180 | 8 | 0 | |
|
Port Lions Port Lions · Kodiak Island Borough County |
175 | 9 | 0 | |
|
Rivers Edge Condominium Eagle River · Anchorage Municipality County |
168 | 1 | 0 | |
|
Deering Utility System Deering · Northwest Arctic Borough County |
160 | 7 | 0 | |
|
Golovin Community Water System Golovin · Nome Census Area County |
150 | 8 | 2 | |
|
Crooked Creek Watering Point Crooked Creek · Bethel Census Area County |
147 | 6 | 1 | |
|
Lksd Kongiganak HS & Elem Kongiganak · Bethel Census Area County |
143 | 5 | 1 | |
|
Chuathbaluk Water System Chuathbaluk · Bethel Census Area County |
123 | 9 | 2 | |
|
Usaf Eareckson Shemya Stations · Aleutians West Census Area County |
120 | 1 | 0 | |
|
Chilkat Indian Village Haines · Haines Borough County |
113 | 10 | 1 | |
|
Hughes Public Water Supply Hughes · Yukon-Koyukuk Census Area County |
107 | 9 | 2 | |
|
Ketchikan Water, Truck 1 Ketchikan · Ketchikan Gateway Borough County |
100 | 2 | 1 | |
|
Anvik Water System Anvik · Yukon-Koyukuk Census Area County |
96 | 8 | 2 | |
|
Akutan Akutan · Aleutians East Borough County |
95 | 10 | 0 | |
|
Port Alexander PWS Port Alexander · Sitka City and Borough County |
95 | 5 | 0 |
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.