TTHM (Total Trihalomethanes) violations in Ohio
102 active public water systems in Ohio had a TTHM (Total Trihalomethanes) violation in the past three years, 6 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 |
|---|---|---|---|---|
|
Hopedale Village PWS Harrison County |
984 | 5 | 1 | |
|
Jefferson CO W&s District J Jefferson County |
896 | 3 | 1 | |
|
Adena Village PWS Jefferson County |
820 | 4 | 2 | |
|
Flushing Village PWS Belmont County |
803 | 5 | 1 | |
|
Marshallville Village PWS Wayne County |
756 | 3 | 2 | |
|
Rock Creek Village Ashtabula County |
667 | 5 | 0 | |
|
Thurston Village PWS Fairfield County |
604 | 5 | 1 | |
|
Pine Ridge MHP Lorain County |
570 | 5 | 4 | |
|
Arcadia Village PWS Hancock County |
564 | 3 | 1 | |
|
Bethel Township Water System PWS Miami County |
543 | 4 | 2 | |
|
Miami Co-Deer Cliff Run PWS Miami County |
526 | 2 | 0 | |
|
Verona, Village of Preble County |
492 | 3 | 1 | |
|
Laura Village PWS Miami County |
487 | 6 | 3 | |
|
Jacksonville Village PWS Athens County |
481 | 3 | 1 | |
|
Brookside Village MHP PWS Clark County |
475 | 4 | 1 | |
|
Port Washington Elem School New PWS Tuscarawas County |
425 | 2 | 1 | |
|
Heatherwood Terrace Townhouses Richland County |
411 | 2 | 1 | |
|
Willshire Village PWS Van Wert County |
405 | 4 | 2 | |
|
Buckeye Trails L Pickaway County |
400 | 6 | 3 | |
|
Shelby County Water and Sewer PWS Shelby County |
375 | 3 | 0 | |
|
Jefferson CO W&s District O Jefferson County |
340 | 4 | 2 | |
|
Buckeye Trails M Pickaway County |
330 | 6 | 2 | |
|
Arrowhead Lake MHP Lucas County |
327 | 2 | 1 | |
|
Wilmot Village PWS Stark County |
325 | 4 | 0 | |
|
Mountainview Mobile Village Logan County |
300 | 5 | 0 | |
|
Fair Haven Shelby County Home Shelby County |
290 | 3 | 1 | |
|
Stoneybrooke Village MHP Trumbull County |
250 | 4 | 0 | |
|
Whitetail Run Homeowners Geauga County |
250 | 2 | 1 | |
|
Pebble Creek Convalescent Center Summit County |
240 | 4 | 1 | |
|
Hayden Heights MHP Franklin County |
188 | 3 | 0 | |
|
Holmes County Jail Holmes County |
180 | 2 | 1 | |
|
Swanton Meadows Fulton County |
180 | 2 | 0 | |
|
Mohican Young Star Academy Ashland County |
150 | 2 | 1 | |
|
Meadow Creek Condo Assoc Portage County |
122 | 2 | 1 | |
|
Grandview Heights Civic Association PWS Champaign County |
120 | 4 | 1 | |
|
Leesville Land LLC Harrison County |
99 | 3 | 0 | |
|
Tammis Mobile Village Ltd. PWS Logan County |
98 | 4 | 2 | |
|
Dayton VA Bldg 320 Pod C Montgomery County |
85 | 2 | 0 | |
|
Dfc Mobile Home Park Ashtabula County |
85 | 4 | 2 | |
|
Deersville Village PWS Harrison County |
82 | 6 | 1 | |
|
Sunset Mobile Home Park Pickaway County |
80 | 3 | 1 | |
|
Sundial Mobile Home Park Wayne County |
75 | 2 | 0 | |
|
Community Gardens MHP Franklin County |
74 | 3 | 0 | |
|
Dayton VA Bldg 320 Pod B Montgomery County |
72 | 2 | 0 | |
|
Dayton VA Bldg 320 Pod D Montgomery County |
68 | 2 | 0 | |
|
Whispering Pines Mobile Home Park Pickaway County |
62 | 4 | 0 | |
|
Indian Lake Rehabilitation Center Logan County |
53 | 3 | 1 | |
|
Waterfall Estates MHP Richland County |
51 | 2 | 1 | |
|
Island Creek Homeowners Mahoning County |
50 | 3 | 1 | |
|
Spring Meadows Care Center Champaign County |
42 | 3 | 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 Ohio 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.