TTHM (Total Trihalomethanes) violations in Illinois
355 active public water systems in Illinois had a TTHM (Total Trihalomethanes) violation in the past three years, 50 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 |
|---|---|---|---|---|
|
Egyptian Water Company Randolph County |
2,543 | 2 | 0 | |
|
Carthage Hancock County |
2,510 | 1 | 0 | |
|
Ewing-Ina Water Commission Franklin County |
2,393 | 2 | 0 | |
|
Dawson Dawson · Sangamon County |
2,375 | 5 | 1 | |
|
Lick Creek Pwd Union County |
2,365 | 2 | 0 | |
|
White Hall White Hall · Greene County |
2,313 | 5 | 0 | |
|
Prospect Heights Prospect Heights · Cook County |
2,280 | 1 | 0 | |
|
Norris City Norris City · White County |
2,155 | 1 | 0 | |
|
Carrier Mills Carrier Mills · Saline County |
2,085 | 1 | 0 | |
|
Henderson Pwd Montgomery County |
2,045 | 4 | 0 | |
|
Jbs Corporation Cass County |
2,000 | 7 | 1 | |
|
Southeast Joliet SD Joliet · Will County |
2,000 | 8 | 3 | |
|
Phoenix Phoenix · Cook County |
1,994 | 4 | 2 | |
|
Merrionette Park Merrionette Park · Cook County |
1,969 | 3 | 2 | |
|
Steeleville Steeleville · Randolph County |
1,960 | 5 | 2 | |
|
Sterling Estates MHP Justice · Cook County |
1,954 | 1 | 0 | |
|
Lexington Lexington · McLean County |
1,930 | 1 | 0 | |
|
Marissa Marissa · St. Clair County |
1,921 | 2 | 1 | |
|
DE Soto De Soto · Jackson County |
1,910 | 1 | 0 | |
|
South Roxana South Roxana · Madison County |
1,891 | 6 | 1 | |
|
Poplar Grove South Poplar Grove · Boone County |
1,877 | 5 | 1 | |
|
Ford Heights East Chicago Heights · Cook County |
1,813 | 4 | 3 | |
|
Chenoa Chenoa · McLean County |
1,800 | 2 | 1 | |
|
Jonesboro Jonesboro · Union County |
1,799 | 1 | 0 | |
|
Gilman Gilman · Iroquois County |
1,793 | 3 | 1 | |
|
Aqua Illinois-Rockwell Lake County |
1,762 | 1 | 0 | |
|
Roodhouse Roodhouse · Greene County |
1,753 | 1 | 0 | |
|
Delavan Delavan · Tazewell County |
1,743 | 1 | 0 | |
|
Cambria Cambria · Williamson County |
1,727 | 1 | 0 | |
|
ST Rose Pwd Clinton County |
1,688 | 6 | 3 | |
|
Pontiac Correctional Center Pontiac · Livingston County |
1,665 | 4 | 1 | |
|
Bement Bement · Piatt County |
1,661 | 3 | 1 | |
|
Shawnee Correctional Center Vienna · Johnson County |
1,617 | 2 | 0 | |
|
Grayville Grayville · White County |
1,613 | 3 | 1 | |
|
Hodgkins Hodgkins · Cook County |
1,597 | 2 | 1 | |
|
Fairfield Rural Waterworks--Jasper Fairfield · Wayne County |
1,578 | 2 | 0 | |
|
Fci-Marion Marion · Williamson County |
1,544 | 3 | 2 | |
|
East Hazel Crest East Hazel Crest · Cook County |
1,500 | 1 | 0 | |
|
Maple Park Maple Park · Kane County |
1,484 | 6 | 1 | |
|
Warsaw Warsaw · Hancock County |
1,480 | 2 | 0 | |
|
Four Seasons MHP Boone County |
1,468 | 3 | 0 | |
|
Silvis Heights Water Corp Rock Island County |
1,450 | 7 | 3 | |
|
South Fulton Water District Fulton County |
1,430 | 1 | 0 | |
|
Murrayville-Woodson Water Commission Morgan County |
1,403 | 3 | 0 | |
|
Hilltop MHP Bloomington · McLean County |
1,360 | 7 | 2 | |
|
Riverdale School District #100 Rock Island County |
1,340 | 10 | 0 | |
|
Walnut Walnut · Bureau County |
1,311 | 2 | 0 | |
|
Milford Milford · Iroquois County |
1,306 | 5 | 2 | |
|
Blue Mound Blue Mound · Macon County |
1,300 | 5 | 3 | |
|
Taylorville Correctional Center Taylorville · Christian County |
1,300 | 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 Illinois 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.