Illinois
DuPage County drinking water quality
208 active public water systems serve 861,290 people in DuPage County. 162 are compliant, 46 had at least one EPA violation in the past three years, 1 is a designated serious violator, and 1 carries a health flag.
Needs attention
Community water systems
48 systems, largest first| System | Serves | Status | Rules violated, 3 yr | Unresolved |
|---|---|---|---|---|
|
Naperville Naperville |
156,406 | 1 | 0 | |
|
Wheaton Wheaton |
53,970 | 1 | 0 | |
|
Downers Grove Downers Grove |
49,425 | 0 | 0 | |
|
Elmhurst Elmhurst |
45,000 | 0 | 0 | |
|
Lombard Lombard |
44,476 | 2 | 2 | |
|
Carol Stream Carol Stream |
39,854 | 3 | 0 | |
|
Addison Addison |
38,017 | 1 | 0 | |
|
Woodridge Woodridge |
33,566 | 1 | 1 | |
|
Glendale Heights Glendale Heights |
33,176 | 1 | 0 | |
|
Glen Ellyn Glen Ellyn |
28,500 | 1 | 1 | |
|
West Chicago West Chicago |
25,166 | 0 | 0 | |
|
Lisle Lisle |
24,223 | 1 | 1 | |
|
Westmont Westmont |
24,161 | 0 | 0 | |
|
Roselle Roselle |
22,897 | 2 | 0 | |
|
Villa Park Villa Park |
22,263 | 0 | 0 | |
|
Bloomingdale Weston |
22,018 | 1 | 1 | |
|
Darien Darien |
21,751 | 1 | 0 | |
|
Bensenville Bensenville |
18,537 | 1 | 0 | |
|
Hinsdale Hinsdale |
17,900 | 1 | 0 | |
|
Wood Dale Wood Dale |
14,012 | 3 | 1 | |
|
Warrenville Warrenville |
12,350 | 1 | 0 | |
|
Burr Ridge Burr Ridge |
11,192 | 1 | 0 | |
|
Winfield Winfield |
9,835 | 0 | 0 | |
|
Itasca Itasca |
9,506 | 0 | 0 | |
|
Oak Brook Oak Brook |
9,400 | 3 | 0 | |
|
Willowbrook Willowbrook |
9,000 | 3 | 2 | |
|
Clarendon Hills Clarendon Hills |
8,702 | 1 | 0 | |
|
Southeast Regional Water Facility |
6,940 | 1 | 0 | |
|
IL American-Valley View |
6,721 | 0 | 0 | |
|
IL American-Dupage Utility |
6,613 | 0 | 0 | |
|
Aqua Illinois-Oak Brook Oak Brook |
5,361 | 0 | 0 | |
|
IL American-Liberty Ridge West |
3,307 | 0 | 0 | |
|
Glen Ellyn Heights Subdivision |
1,931 | 4 | 1 | |
|
Steeple Run Sbdv |
1,931 | 1 | 0 | |
|
IL American-Arrowhead |
1,581 | 0 | 0 | |
|
Oakbrook Terrace Oak Brook Terr |
1,440 | 0 | 0 | |
|
York Township Water System Oak Brook Terr |
1,423 | 1 | 1 | |
|
IL American-Country Club |
1,014 | 0 | 0 | |
|
Liberty Park Homeowners Association |
950 | 3 | 1 | |
|
North Regional Water Fac |
770 | 1 | 0 | |
|
IL American-Lombard Heights Lombard |
679 | 0 | 0 | |
|
IL American-Clarendon |
625 | 2 | 0 | |
|
Hobson Valley Water System |
400 | 0 | 0 | |
|
IL American-Liberty Ridge East Wheaton |
320 | 0 | 0 | |
|
Pleasant Ridge MHP |
284 | 2 | 1 | |
|
Wood Dale Estates |
145 | 4 | 0 | |
|
Polo DR and Saddle RD Subdivision |
93 | 0 | 0 | |
|
DU Page Water Commission |
1 | 0 | 0 |
Non-community systems (160: schools, campgrounds, workplaces, restaurants)
These systems serve places people visit rather than homes.
Inactive systems (1,125, no longer operating or reporting)
Kept for the record and excluded from the county totals above. Browse inactive systems.
About this data
Totals cover active systems. Systems serving more than one county are counted in each county. EPA counts the rules a system was in violation of, not the individual violations; one rule can carry several.
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.