COUNTY WATER-SYSTEM LEDGER
Cook, Illinois
EPA’s September 2026 export lists 113 active community water systems serving Cook, Illinois, with 65 current-violation flags and 1 serious-violator flags among the covered systems.
Source: EPA SDWIS system-search export · Active community systems serving 2,500+ people · Snapshot 13 Sep 2026
Systems113active CWS · pop. 2,500+
Population served5,180,585reported total; may overlap
Current violation flag57.5%65 systems
Serious-violator flag0.9%1 systems
01 / SYSTEMS
Water systems serving Cook, Illinois
EPA associates 113 covered systems with Cook, Illinois; their reported population-served values total 5,180,585 and may overlap.
Ordered by reported population served. Open any record for separate health, monitoring, notice, other, and serious-violator flags.
| Water system | Population served | Primary source | Current export status |
|---|---|---|---|
| ChicagoIL0316000 | 2,721,308 | Surface water | No current violation flagged |
| CiceroIL0310510 | 83,000 | Surface water purchased | Current monitoring/reporting flag |
| SchaumburgIL0314890 | 75,750 | Surface water purchased | No current violation flagged |
| EvanstonIL0310810 | 74,486 | Surface water | No current violation flagged |
| Arlington HeightsIL0314030 | 73,320 | Surface water purchased | Other current violation flag |
| PalatineIL0312340 | 70,875 | Surface water purchased | No current violation flagged |
| SkokieIL0312880 | 66,422 | Surface water purchased | Current monitoring/reporting flag |
| Des PlainesIL0310630 | 60,675 | Surface water purchased | Current monitoring/reporting flag |
| Oak LawnIL0312220 | 58,362 | Surface water purchased | Other current violation flag |
| Orland ParkIL0312310 | 58,020 | Surface water purchased | Other current violation flag |
| BerwynIL0310210 | 57,250 | Surface water purchased | Current monitoring/reporting flag |
| Tinley ParkIL0314910 | 56,703 | Surface water purchased | Other current violation flag |
| Oak ParkIL0312250 | 54,583 | Surface water purchased | No current violation flagged |
| Hoffman EstatesIL0311290 | 50,179 | Surface water purchased | No current violation flagged |
| GlenviewIL0311020 | 47,856 | Surface water purchased | Other current violation flag |
| Buffalo GroveIL0314180 | 43,212 | Surface water purchased | No current violation flagged |
| BartlettIL0314120 | 41,500 | Surface water purchased | No current violation flagged |
| Mount ProspectIL0311980 | 41,000 | Surface water purchased | Other current violation flag |
| Park RidgeIL0312460 | 39,800 | Surface water purchased | Other current violation flag |
| WheelingIL0314970 | 39,725 | Surface water purchased | No current violation flagged |
| StreamwoodIL0313060 | 39,577 | Surface water purchased | No current violation flagged |
| Hanover ParkIL0314480 | 37,470 | Surface water purchased | Other current violation flag |
| Calumet CityIL0310390 | 37,000 | Surface water purchased | Current health-based flag |
| NorthbrookIL0312070 | 34,407 | Surface water | No current violation flagged |
| Elk Grove VillageIL0314400 | 31,802 | Surface water purchased | Other current violation flag |
| Aqua Illinois-North Maine UtilitiesIL0315350 | 30,043 | Surface water purchased | No current violation flagged |
| South Stickny SdIL0317370 | 30,000 | Surface water purchased | Other current violation flag |
| NilesIL0312010 | 29,350 | Surface water purchased | Other current violation flag |
| LansingIL0311590 | 29,076 | Surface water purchased | Current monitoring/reporting flag |
| Oak ForestIL0312190 | 27,478 | Surface water purchased | Current monitoring/reporting flag |
| WilmetteIL0313300 | 27,087 | Surface water | Other current violation flag |
| Chicago HeightsIL0310450 | 26,184 | Surface water purchased | Current monitoring/reporting flag |
| Morton GroveIL0311950 | 25,297 | Surface water purchased | Other current violation flag |
| Elmwood ParkIL0310780 | 25,000 | Surface water purchased | Other current violation flag |
| HarveyIL0311110 | 25,000 | Surface water purchased | Current monitoring/reporting flag |
| Melrose ParkIL0311860 | 24,206 | Surface water purchased | No current violation flagged |
| MaywoodIL0311830 | 24,090 | Surface water purchased | Current health-based flag |
| Rolling MeadowsIL0312730 | 23,329 | Surface water purchased | Other current violation flag |
| South HollandIL0312970 | 22,000 | Surface water purchased | Other current violation flag |
| Park ForestIL0314740 | 21,687 | Ground water | No current violation flagged |
| Blue IslandIL0310240 | 21,494 | Surface water purchased | No current violation flagged |
| DoltonIL0310690 | 20,510 | Surface water purchased | Current monitoring/reporting flag |
| Evergreen ParkIL0310840 | 19,943 | Surface water purchased | No current violation flagged |
| HomewoodIL0311350 | 19,463 | Surface water purchased | Other current violation flag |
| BellwoodIL0310150 | 19,156 | Surface water purchased | Other current violation flag |
| AlsipIL0310030 | 19,063 | Surface water purchased | No current violation flagged |
| BrookfieldIL0310330 | 18,776 | Surface water purchased | No current violation flagged |
| Palos HillsIL0312400 | 18,530 | Surface water purchased | No current violation flagged |
| Franklin ParkIL0310960 | 18,467 | Surface water purchased | Current monitoring/reporting flag |
| Justice-Willow Springs Water CommissionIL0315820 | 18,450 | Surface water purchased | No current violation flagged |
| MattesonIL0311800 | 18,293 | Surface water purchased | Current monitoring/reporting flag |
| LemontIL0311620 | 17,500 | Ground water | No current violation flagged |
| Country Club HillsIL0310540 | 16,500 | Surface water purchased | Other current violation flag |
| BridgeviewIL0310270 | 16,467 | Surface water purchased | No current violation flagged |
| WestchesterIL0313150 | 16,241 | Surface water purchased | Current monitoring/reporting flag |
| La GrangeIL0311530 | 16,200 | Surface water purchased | Current monitoring/reporting flag |
| Palos HeightsIL0312370 | 15,500 | Surface water purchased | Other current violation flag |
| NorridgeIL0312040 | 15,251 | Surface water purchased | No current violation flagged |
| MidlothianIL0311920 | 14,819 | Surface water purchased | Current monitoring/reporting flag |
| Hickory HillsIL0311200 | 14,505 | Surface water purchased | No current violation flagged |
Showing the 60 largest systems by reported population served.
02 / SOURCE MIX
Primary water sources for Cook, Illinois
EPA classifies 113 systems serving Cook, Illinois across 3 primary-source categories; Surface water is the largest category with 6 systems.
How to read the population total
It is the sum of each listed system's reported population served, not a census estimate. Service areas can overlap and some systems list multiple cities or counties.