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 |
|---|---|---|---|---|
|
Seaport Lakes Subdivision Calhoun County |
36 | 10 | 4 | |
|
City of Freeport Slaughter Road Brazoria County |
32 | 3 | 0 | |
|
Clara Hills Water System Burleson County |
28 | 3 | 1 | |
|
Hockley Data Center Harris County |
25 | 3 | 2 | |
|
Kermier Commerce Center Harris County |
25 | 1 | 0 | |
|
Willowbreeze Farm Subdivision Brazoria County |
20 | 3 | 1 | |
|
Guadalupe Blanco River Authority Calhoun County |
0 | 5 | 2 | |
|
North Alamo WSC Hidalgo County |
171,195 | 3 | 0 | |
|
City of San Angelo Tom Green County |
105,229 | 5 | 0 | |
|
City of Edinburg Hidalgo County |
85,224 | 3 | 0 | |
|
City of Mission Hidalgo County |
77,058 | 2 | 0 | |
|
City of San Marcos Hays County |
72,970 | 1 | 0 | |
|
City of Pflugerville Travis County |
63,464 | 3 | 0 | |
|
Springs Hill SUD Guadalupe County |
35,541 | 4 | 2 | |
|
Goforth SUD Hays County |
34,893 | 3 | 0 | |
|
City of Seguin Guadalupe County |
32,736 | 1 | 0 | |
|
City of Palestine Anderson County |
31,272 | 4 | 0 | |
|
City of Kerrville Kerr County |
30,530 | 3 | 0 | |
|
City of Boerne Kendall County |
24,769 | 1 | 0 | |
|
City of Nederland Jefferson County |
18,157 | 3 | 1 | |
|
Fort Bend County MUD 30 Fort Bend County |
16,794 | 1 | 0 | |
|
Maxwell SUD Caldwell County |
16,104 | 2 | 0 | |
|
Nueces County Wcid 4 Nueces County |
14,880 | 1 | 0 | |
|
East Cedar Creek Fwsd Brookshire Henderson County |
14,823 | 5 | 0 | |
|
City of Jacksonville Cherokee County |
14,420 | 3 | 0 | |
|
Harris County MUD 285 Harris County |
14,268 | 2 | 0 | |
|
City of Beeville Bee County |
13,664 | 5 | 2 | |
|
City of Bastrop Bastrop County |
13,209 | 2 | 0 | |
|
City of Mont Belvieu Chambers County |
12,864 | 2 | 1 | |
|
BI County WSC 1 Camp County |
12,777 | 3 | 1 | |
|
City of Bonham Fannin County |
10,746 | 2 | 0 | |
|
City of Bellmead McLennan County |
10,664 | 6 | 1 | |
|
City of Freeport Brazoria County |
10,594 | 3 | 2 | |
|
Mission Bend MUD 2 Harris County |
10,155 | 2 | 0 | |
|
Rice University Harris County |
8,415 | 5 | 0 | |
|
Parkway UD Harris County |
7,323 | 1 | 0 | |
|
City of Lampasas Lampasas County |
7,291 | 4 | 0 | |
|
Bell Milam Falls WSC Bell County |
6,885 | 5 | 0 | |
|
City of Granite Shoals Burnet County |
6,795 | 4 | 2 | |
|
West Harris County MUD 10 Harris County |
6,697 | 1 | 0 | |
|
Kaufman County MUD 14 Kaufman County |
6,456 | 2 | 1 | |
|
EL Oso WSC Karnes County |
6,288 | 2 | 0 | |
|
Riverside SUD Walker County |
6,246 | 3 | 0 | |
|
Jackson WSC Smith County |
5,862 | 4 | 0 | |
|
Williamson Travis County MUD 1 Williamson County |
5,793 | 1 | 0 | |
|
Village of Surfside Beach Brazoria County |
5,697 | 3 | 1 | |
|
Oak Trail Shores Hood County |
5,676 | 3 | 0 | |
|
City of Marlin Falls County |
5,516 | 5 | 3 | |
|
City of Cameron Milam County |
5,489 | 4 | 3 | |
|
City of Post Garza County |
5,471 | 3 | 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.