TTHM (Total Trihalomethanes) violations in South Dakota
31 active public water systems in South Dakota had a TTHM (Total Trihalomethanes) violation in the past three years. What TTHM (Total Trihalomethanes) is and why it matters.
Systems with a TTHM (Total Trihalomethanes) violation
Unresolved first, then largest first| System | Serves | Status | Rules violated, 3 yr | Unresolved |
|---|---|---|---|---|
|
Eagle Butte Eagle Butte · Dewey County |
4,000 | 3 | 0 | |
|
Mission Water System County |
2,500 | 4 | 0 | |
|
Parkston Parkston · Hutchinson County |
1,567 | 2 | 0 | |
|
Fort Thompson Water System County |
1,375 | 1 | 0 | |
|
Platte Platte · Charles Mix County |
1,256 | 1 | 0 | |
|
Howard Howard · Miner County |
848 | 2 | 0 | |
|
Alcester Alcester · Union County |
820 | 2 | 0 | |
|
Wanblee Water System County |
773 | 1 | 0 | |
|
Crow Creek Tribal School County |
516 | 5 | 0 | |
|
Perkins County Rural Water Bison · Perkins County |
470 | 1 | 0 | |
|
Crazy Horse School County |
428 | 4 | 1 | |
|
Tabor Tabor · Bon Homme County |
423 | 1 | 0 | |
|
Allen Water System County |
420 | 2 | 0 | |
|
Marty Water System County |
420 | 4 | 0 | |
|
American Horse School County |
400 | 2 | 0 | |
|
Flandreau School County |
375 | 4 | 1 | |
|
Pine Ridge Hospital County |
316 | 7 | 0 | |
|
Wounded Knee District School County |
280 | 2 | 0 | |
|
Lake Andes Tribal Housing Water System County |
264 | 4 | 0 | |
|
Wounded Knee Water System County |
255 | 3 | 0 | |
|
Wagner South Housing Water System County |
200 | 4 | 0 | |
|
Wagner North Housing Water System County |
180 | 4 | 0 | |
|
Crow Creek Sioux Tribe Water System County |
130 | 2 | 0 | |
|
Red Rocks Water System County |
125 | 3 | 0 | |
|
Midland Midland · Haakon County |
120 | 1 | 0 | |
|
Wakpamni Water System County |
104 | 3 | 0 | |
|
Potato Creek Water System County |
95 | 1 | 0 | |
|
Corona Corona · Roberts County |
69 | 4 | 0 | |
|
North Allen Water System County |
65 | 5 | 0 | |
|
Wolf Creek Water System County |
65 | 3 | 0 | |
|
Garden City Garden City · Clark County |
33 | 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 South Dakota 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. Retrieved from ECHO on Oct 11, 2026.