TTHM (Total Trihalomethanes) violations in Wisconsin
59 active public water systems in Wisconsin had a TTHM (Total Trihalomethanes) violation in the past three years, 3 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 |
|---|---|---|---|---|
|
Oakton Beach Pewaukee · Waukesha County |
144 | 1 | 0 | |
|
Dodge Sanitary Dist 1 Dodge · Trempealeau County |
120 | 5 | 1 | |
|
Lowenstine Fund Corporation Land O Lakes · Vilas County |
120 | 1 | 0 | |
|
Grande Cheese Company Juda · Green County |
110 | 4 | 1 | |
|
Red Wing County |
100 | 1 | 0 | |
|
Manitou Falls Sanitary District NO 1 Superior · Douglas County |
95 | 10 | 5 | |
|
Northland Mission Dunbar · Marinette County |
75 | 7 | 0 | |
|
3m CO Greystone Plant Wausau · Marathon County |
52 | 3 | 1 | |
|
Kingston Cheese Co-Op Cambria · Green Lake County |
36 | 1 | 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 Wisconsin 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.