All water systems in Illinois
5,097 systems
| System | Serves | Status | Rules violated, 3 yr | Unresolved |
|---|---|---|---|---|
|
Chicago Cook County |
2,721,308 | 4 | 0 | |
|
Aurora Aurora · Kane County |
183,000 | 0 | 0 | |
|
Joliet Joliet · Will County |
160,000 | 4 | 0 | |
|
Naperville Naperville · DuPage County |
156,406 | 1 | 0 | |
|
IL American-Champaign Champaign · Champaign County |
150,000 | 0 | 0 | |
|
Rockford Rockford · Winnebago County |
147,051 | 3 | 0 | |
|
IL American-Peoria Peoria · Peoria County |
137,575 | 0 | 0 | |
|
IL American-East ST Louis East St Louis · St. Clair County |
131,368 | 0 | 0 | |
|
Springfield Springfield · Sangamon County |
117,444 | 2 | 0 | |
|
Elgin Elgin · Kane County |
114,797 | 3 | 0 | |
|
Waukegan Waukegan · Lake County |
87,149 | 3 | 1 | |
|
Cicero Cicero · Cook County |
83,000 | 4 | 1 | |
|
Aqua Illinois-Kankakee Kankakee · Kankakee County |
80,000 | 5 | 0 | |
|
Bloomington Bloomington · McLean County |
79,000 | 2 | 0 | |
|
Decatur Decatur · Macon County |
76,122 | 1 | 0 | |
|
Schaumburg Schaumburg · Cook County |
75,750 | 1 | 0 | |
|
Evanston Evanston · Cook County |
74,486 | 0 | 0 | |
|
IL American-West Suburban Bolingbrook · Will County |
73,978 | 0 | 0 | |
|
Arlington Heights Arlington Heights · Cook County |
73,320 | 3 | 2 | |
|
Palatine Palatine · Cook County |
70,875 | 0 | 0 | |
|
Skokie Skokie · Cook County |
66,422 | 4 | 1 | |
|
Des Plaines Des Plaines · Cook County |
60,675 | 3 | 2 | |
|
Oak Lawn Oak Lawn · Cook County |
58,362 | 1 | 1 | |
|
Orland Park Orland Park · Cook County |
58,020 | 1 | 1 | |
|
Berwyn Berwyn · Cook County |
57,250 | 3 | 0 | |
|
Tinley Park Tinley Park · Cook County |
56,703 | 3 | 1 | |
|
Oak Park Oak Park · Cook County |
54,583 | 0 | 0 | |
|
Wheaton Wheaton · DuPage County |
53,970 | 1 | 0 | |
|
Normal Normal · McLean County |
52,736 | 0 | 0 | |
|
Romeoville Romeoville · Will County |
50,458 | 0 | 0 | |
|
Hoffman Estates Hoffman Estates · Cook County |
50,179 | 0 | 0 | |
|
Plainfield Plainfield · Will County |
50,000 | 1 | 0 | |
|
Downers Grove Downers Grove · DuPage County |
49,425 | 0 | 0 | |
|
Glenview Glenview · Cook County |
47,856 | 2 | 0 | |
|
O Fallon O Fallon · St. Clair County |
46,603 | 1 | 0 | |
|
IL American-Alton Alton · Madison County |
46,127 | 0 | 0 | |
|
Elmhurst Elmhurst · DuPage County |
45,000 | 0 | 0 | |
|
Moline Moline · Rock Island County |
44,500 | 2 | 0 | |
|
Lombard Lombard · DuPage County |
44,476 | 2 | 2 | |
|
Buffalo Grove Buffalo Grove · Cook County |
43,212 | 2 | 0 | |
|
Quincy Quincy · Adams County |
42,000 | 1 | 1 | |
|
Bartlett Bartlett · Cook County |
41,500 | 1 | 0 | |
|
Mount Prospect Mount Prospect · Cook County |
41,000 | 3 | 1 | |
|
Crystal Lake Crystal Lake · McHenry County |
40,661 | 1 | 0 | |
|
Dekalb De Kalb · DeKalb County |
40,290 | 1 | 0 | |
|
Carol Stream Carol Stream · DuPage County |
39,854 | 3 | 0 | |
|
Park Ridge Park Ridge · Cook County |
39,800 | 1 | 1 | |
|
Wheeling Wheeling · Cook County |
39,725 | 0 | 0 | |
|
Rock Island Rock Island · Rock Island County |
39,018 | 3 | 1 | |
|
Streamwood Streamwood · Cook County |
38,360 | 0 | 0 |
About this data
Rules violated counts the rules a system was in violation of in the past three years, including monitoring and reporting lapses; one rule can carry several violations. Unresolved is the number of those rules still in violation at EPA's latest data refresh.
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. Retrieved from ECHO on Oct 11, 2026.