TTHM (Total Trihalomethanes) violations in Missouri
107 active public water systems in Missouri had a TTHM (Total Trihalomethanes) violation in the past three years, 18 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 |
|---|---|---|---|---|
|
Monroe City PWS Monroe City · Monroe County |
2,500 | 4 | 0 | |
|
Daviess County Pwsd 2 Jameson · Daviess County |
2,448 | 1 | 0 | |
|
Memphis PWS Memphis · Scotland County |
1,822 | 7 | 0 | |
|
MO American Ironton Ironton · Iron County |
1,460 | 2 | 0 | |
|
Platte County Pwsd 8 Edgerton · Platte County |
1,200 | 1 | 0 | |
|
Maysville PWS Maysville · DeKalb County |
1,096 | 5 | 0 | |
|
Clinton County Pwsd 4 Sys 2 Lathrop · Clinton County |
840 | 4 | 2 | |
|
Bates County Pwsd 2 Amsterdam · Bates County |
752 | 6 | 0 | |
|
Hopkins PWS Hopkins · Nodaway County |
550 | 7 | 2 | |
|
Keytesville PWS Keytesville · Chariton County |
500 | 4 | 1 | |
|
Freeman PWS Freeman · Cass County |
482 | 6 | 2 | |
|
Gilman City PWS Harrison County |
380 | 2 | 0 | |
|
Blodgett PWS Blodgett · Scott County |
300 | 8 | 1 | |
|
Callao PWS Callao · Macon County |
248 | 5 | 1 | |
|
Arrow Rock PWS Arrow Rock · Saline County |
235 | 4 | 1 | |
|
Emma PWS Emma · Lafayette County |
205 | 3 | 2 | |
|
Amoret PWS Amoret · Bates County |
190 | 2 | 0 | |
|
Blairstown PWS Blairstown · Henry County |
123 | 4 | 1 | |
|
Washington PWS Washington · Franklin County |
14,068 | 4 | 0 | |
|
Jefferson County Pwsd 10 Jefferson County |
10,000 | 1 | 0 | |
|
Waynesville PWS Waynesville · Pulaski County |
5,460 | 3 | 1 | |
|
Clinton CO Pwsd 4 Sys 1 Lathrop · Clinton County |
4,968 | 5 | 2 | |
|
Moscow Mills PWS Moscow Mills · Lincoln County |
4,500 | 3 | 0 | |
|
Knox County Public Water & Sewer Dist 1 Knox City · Knox County |
3,947 | 4 | 2 | |
|
Harrison County Pwsd 2 Bethany · Harrison County |
3,740 | 4 | 0 | |
|
ST Charles CO Pwsd #2 Wright City Wright City · Warren County |
3,550 | 1 | 0 | |
|
Farmington Correctional Center Farmington · St. Francois County |
3,500 | 5 | 2 | |
|
Franklin County Pwsd 1 Washington · Franklin County |
3,500 | 1 | 0 | |
|
Jasper County Pwsd 2 Webb City · Jasper County |
3,383 | 1 | 0 | |
|
Louisiana PWS Louisiana · Pike County |
3,244 | 7 | 0 | |
|
Buckner PWS Buckner · Jackson County |
3,076 | 2 | 0 | |
|
Mississippi County Pwsd 1 Mississippi County |
3,000 | 6 | 3 | |
|
Bates County Pwsd 4 Foster · Bates County |
2,348 | 2 | 0 | |
|
Big Lake Village of PWS Big Lake · Holt County |
2,000 | 3 | 0 | |
|
Jasper County Pwsd 3 Jasper County |
1,900 | 3 | 0 | |
|
Hamilton PWS Hamilton · Caldwell County |
1,813 | 2 | 0 | |
|
Senath PWS Senath · Dunklin County |
1,767 | 9 | 0 | |
|
Adrian PWS Adrian · Bates County |
1,635 | 7 | 2 | |
|
Worth County Pwsd 1 Grant City · Worth County |
1,497 | 3 | 0 | |
|
MO Ark Water CO Blue Eye · Stone County |
1,478 | 4 | 0 | |
|
Linn County Cons Pwsd 1 Purdin · Linn County |
1,420 | 4 | 0 | |
|
Sweet Springs PWS Sweet Springs · Saline County |
1,309 | 3 | 1 | |
|
Archie PWS Archie · Cass County |
1,300 | 5 | 2 | |
|
Camden County Pwsd 1 Macks Creek · Camden County |
1,300 | 4 | 1 | |
|
Oran PWS Oran · Scott County |
1,294 | 5 | 0 | |
|
Pierce City PWS Pierce City · Lawrence County |
1,200 | 6 | 2 | |
|
Smithfield Fresh Meats Corp Sullivan County |
1,200 | 1 | 0 | |
|
Holt County Pwsd 1 Holt County |
1,140 | 1 | 0 | |
|
Pettis/johnson/saline Pwsd 1 Saline · Johnson County |
1,000 | 3 | 1 | |
|
New London PWS New London · Ralls County |
975 | 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 Missouri 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.