TTHM (Total Trihalomethanes) violations in Texas
514 active public water systems in Texas had a TTHM (Total Trihalomethanes) violation in the past three years, 157 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 |
|---|---|---|---|---|
|
City of Atlanta Cass County |
5,418 | 5 | 1 | |
|
Fort Bend County MUD 118 Fort Bend County |
5,346 | 1 | 0 | |
|
Goodfellow Air Force Base Tom Green County |
5,241 | 4 | 1 | |
|
West Gregg SUD Gregg County |
5,127 | 2 | 0 | |
|
City of Mathis San Patricio County |
5,001 | 6 | 0 | |
|
Dobbin Plantersville WSC 1 Montgomery County |
4,767 | 4 | 0 | |
|
Harris County MUD 501 Harris County |
4,740 | 1 | 0 | |
|
City of Taft San Patricio County |
4,627 | 5 | 0 | |
|
Jefferson County Wcid 10 Jefferson County |
4,605 | 4 | 0 | |
|
Clay Road MUD Harris County |
4,443 | 1 | 0 | |
|
City of Karnes City Karnes County |
4,269 | 5 | 1 | |
|
City of Comanche Comanche County |
4,211 | 6 | 0 | |
|
Alabama Coushatta #1 (eastside) County |
4,104 | 1 | 0 | |
|
Cross Roads SUD Rusk County |
4,062 | 4 | 1 | |
|
Laughlin Air Force Base Val Verde County |
4,010 | 2 | 0 | |
|
San Antonio Military Medical Center Bexar County |
4,000 | 2 | 0 | |
|
Tpwd Palo Duro Canyon State Park Randall County |
3,964 | 5 | 1 | |
|
Eula WSC Callahan County |
3,918 | 4 | 2 | |
|
Carolynn Estates Henderson County |
3,906 | 3 | 1 | |
|
The Consolidated WSC Central System Houston County |
3,878 | 6 | 1 | |
|
City of Clyde Callahan County |
3,820 | 5 | 1 | |
|
Lometa Regional Water Lampasas County |
3,609 | 3 | 1 | |
|
City of Ballinger Runnels County |
3,583 | 5 | 2 | |
|
Gum Springs WSC 1 Harrison County |
3,564 | 2 | 0 | |
|
City of Coahoma Howard County |
3,552 | 3 | 1 | |
|
Oakmont Pud Harris County |
3,450 | 4 | 0 | |
|
Cherokee Shores Water Supply Henderson County |
3,402 | 2 | 0 | |
|
Ricardo WSC Kleberg County |
3,396 | 3 | 0 | |
|
City of Dublin Erath County |
3,388 | 4 | 1 | |
|
Harris County Wcid Fondren Road Harris County |
3,144 | 2 | 1 | |
|
Upper Leon River Mwd Comanche County |
3,018 | 2 | 0 | |
|
Harris County Facility & Property Mgmt Harris County |
3,000 | 6 | 0 | |
|
E M C Water Supply Marion County |
2,952 | 3 | 0 | |
|
City of Hamilton Hamilton County |
2,895 | 4 | 1 | |
|
City of Santa Rosa Cameron County |
2,883 | 5 | 3 | |
|
City of la Villa Hidalgo County |
2,781 | 3 | 0 | |
|
Fountainview Subdivision Harris County |
2,703 | 4 | 1 | |
|
Violet WSC Nueces County |
2,670 | 5 | 0 | |
|
Cinco MUD 5 Fort Bend County |
2,460 | 2 | 0 | |
|
Lakeside Wcid 2d Travis County |
2,385 | 2 | 0 | |
|
Gbra Johnson Ranch Subdivision Comal County |
2,322 | 1 | 0 | |
|
Rra Preston Shores Water System Grayson County |
2,277 | 2 | 0 | |
|
Central Washington County WSC Washington County |
2,270 | 4 | 0 | |
|
EL Sauz WSC Starr County |
2,223 | 4 | 1 | |
|
Dow Chemical Sabine River Operations Orange County |
2,200 | 2 | 0 | |
|
City of de Leon Comanche County |
2,171 | 3 | 0 | |
|
City of San Augustine San Augustine County |
1,971 | 5 | 1 | |
|
Garfield WSC Travis County |
1,950 | 5 | 1 | |
|
South Rusk County WSC Rusk County |
1,947 | 5 | 0 | |
|
City of Huxley Shelby County |
1,930 | 2 | 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 Texas 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.