Systems reaching a study comparison level
3.0%13 of 436 active community water systems with complete monitoring
All 436 systems had complete monitoring. 13 reached at least one study comparison level; 423 did not. “Study comparison level” means the dated EPA technical cutoff used in this January 2026 research release. It does not determine household exposure, health risk, or current legal compliance.
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ZIP codes are used only to route visitors to public water systems that reported serving them. Confirm the actual provider using a water bill or utility record.
Compound summary
System counts in Illinois
Each count shows how many included water systems reached the named study level.
| Study comparison | Systems reaching level | Water systems included | Percent |
|---|---|---|---|
| PFOA: study level 4.05 ppt (April 2024 EPA level: 4 ppt) | 9 | 436 | 2.1% |
| PFOS: study level 4.05 ppt (April 2024 EPA level: 4 ppt) | 7 | 436 | 1.6% |
| PFHxS: study level 15 ppt (April 2024 EPA level: 10 ppt) | 1 | 436 | 0.2% |
| PFNA: study level 15 ppt (April 2024 EPA level: 10 ppt) | 0 | 436 | 0.0% |
| HFPO-DA: study level 15 ppt (April 2024 EPA level: 10 ppt) | 0 | 436 | 0.0% |
| Hazard Index: study level 1.5 with at least two detected components (April 2024 EPA level: 1) | 1 | 436 | 0.2% |
System directory
Community water systems with complete monitoring
Each PWSID appears once, preventing double counting across ZIP associations.
| Public water system | PWSID | Population served | Primary source | Sampling locations | Study comparison |
|---|---|---|---|---|---|
| ABINGDON | IL0950050 | 3,275 | Ground water purchased | 1 | Reached a study level |
| ABS WATER COOP | IL0015350 | 6,858 | Ground water purchased | 5 | Below the study levels |
| ADDISON | IL0430050 | 38,017 | Surface water purchased | 1 | Below the study levels |
| ALEXANDER WATER DISTRICT | IL1370020 | 442 | Surface water purchased | 1 | Below the study levels |
| ALGONQUIN | IL1110050 | 30,700 | Ground water | 4 | Below the study levels |
| ALSIP | IL0310030 | 19,063 | Surface water purchased | 1 | Below the study levels |
| ALTONA | IL0950100 | 483 | Ground water | 1 | Below the study levels |
| AMERICAN WATER OPER AND MAINTENANCE, LLC | IL1635237 | 6,779 | Surface water purchased | 1 | Below the study levels |
| ANNA | IL1810050 | 4,910 | Ground water purchased | 1 | Below the study levels |
| ANTIOCH | IL0970050 | 14,175 | Ground water | 7 | Below the study levels |
| AQUA ILLINOIS-CANDLEWICK DVN | IL0075050 | 6,426 | Ground water | 1 | Below the study levels |
| AQUA ILLINOIS-KANKAKEE | IL0915030 | 80,000 | Surface water | 1 | Below the study levels |
| AQUA ILLINOIS-NORTH MAINE UTILITIES | IL0315350 | 30,043 | Surface water purchased | 2 | Below the study levels |
| AQUA ILLINOIS-PEOTONE | IL1970750 | 4,182 | Surface water purchased | 2 | Below the study levels |
| AQUA ILLINOIS-UNIVERSITY PARK | IL1975030 | 7,002 | Surface water purchased | 1 | Below the study levels |
| AQUA ILLINOIS-VERMILION COUNTY | IL1835120 | 30,106 | Surface water | 1 | Below the study levels |
| AQUA ILLINOIS-WILLOWBROOK | IL1977870 | 5,100 | Ground water | 3 | Below the study levels |
| ARLINGTON HEIGHTS | IL0314030 | 73,320 | Surface water purchased | 1 | Below the study levels |
| ASHKUM | IL0750050 | 724 | Ground water | 2 | Below the study levels |
| ATHENS | IL1290050 | 4,575 | Ground water | 1 | Below the study levels |
| AUBURN, IL | IL1670050 | 4,574 | Surface water purchased | 1 | Below the study levels |
| AURORA | IL0894070 | 183,000 | Surface water | 1 | Below the study levels |
| BARRINGTON | IL0974080 | 10,327 | Ground water | 2 | Below the study levels |
| BARTLETT | IL0314120 | 41,500 | Surface water purchased | 1 | Below the study levels |
| BATAVIA | IL0894130 | 26,098 | Ground water | 1 | Below the study levels |
| BEARDSTOWN | IL0170150 | 5,951 | Ground water | 1 | Below the study levels |
| BEECHER | IL1970050 | 4,713 | Ground water | 3 | Below the study levels |
| BELVIDERE | IL0070050 | 25,339 | Ground water | 5 | Below the study levels |
| BENSENVILLE | IL0434140 | 18,537 | Surface water purchased | 1 | Below the study levels |
| BERKELEY | IL0310180 | 5,214 | Surface water purchased | 1 | Below the study levels |
| BETHALTO | IL1190150 | 15,210 | Ground water | 1 | Below the study levels |
| BLANDINSVILLE | IL1090100 | 569 | Surface water | 1 | Below the study levels |
| BLOOMINGDALE | IL0430100 | 22,018 | Surface water purchased | 1 | Below the study levels |
| BLOOMINGTON, IL | IL1130200 | 77,610 | Surface water | 1 | Below the study levels |
| BLUE ISLAND | IL0310240 | 21,494 | Surface water purchased | 1 | Below the study levels |
| BLUFFS | IL1710100 | 748 | Ground water | 1 | Below the study levels |
| BOND/MADISON WATER COMPANY | IL0050020 | 6,645 | Surface water purchased | 1 | Below the study levels |
| BOOKWALTER WOODS MHP | IL0635125 | 389 | Ground water | 1 | Below the study levels |
| BRAIDWOOD | IL1970150 | 6,194 | Ground water | 1 | Below the study levels |
| BREESE | IL0270250 | 4,772 | Surface water | 1 | Below the study levels |
| BRIDGEVIEW | IL0310270 | 16,467 | Surface water purchased | 1 | Below the study levels |
| BRIGHTON | IL1174160 | 5,041 | Surface water purchased | 1 | Below the study levels |
| BROADVIEW | IL0310300 | 7,847 | Surface water purchased | 1 | Below the study levels |
| BROOKFIELD | IL0310330 | 18,776 | Surface water purchased | 1 | Below the study levels |
| BUCKLEY | IL0750150 | 500 | Ground water | 1 | Below the study levels |
| BUDA | IL0110100 | 482 | Ground water | 1 | Below the study levels |
| BUFFALO GROVE | IL0314180 | 43,212 | Surface water purchased | 1 | Below the study levels |
| BURNHAM | IL0310360 | 3,989 | Surface water purchased | 2 | Below the study levels |
| BURR RIDGE | IL0434190 | 11,192 | Surface water purchased | 1 | Below the study levels |
| BUSHNELL | IL1090150 | 2,972 | Ground water | 1 | Below the study levels |
| BYRON, IL | IL1410100 | 3,784 | Ground water | 3 | Below the study levels |
| CAHOKIA HEIGHTS | IL1635000 | 12,528 | Surface water purchased | 1 | Below the study levels |
| CALHOUN COUNTY RWD | IL0130010 | 4,675 | Ground water | 1 | Below the study levels |
| CALUMET CITY | IL0310390 | 37,000 | Surface water purchased | 2 | Below the study levels |
| CALUMET PARK | IL0310420 | 8,442 | Surface water purchased | 1 | Below the study levels |
| CANTON, IL | IL0570250 | 16,748 | Groundwater under influence of surface water | 1 | Below the study levels |
| CARBONDALE | IL0770150 | 22,107 | Surface water | 1 | Below the study levels |
| CARLINVILLE | IL1170150 | 6,598 | Surface water | 1 | Below the study levels |
| CARLYLE | IL0270300 | 3,373 | Surface water | 1 | Below the study levels |
| CARMI | IL1930100 | 6,307 | Ground water | 1 | Below the study levels |
| CAROL STREAM | IL0430200 | 39,854 | Surface water purchased | 2 | Below the study levels |
| CARPENTERSVILLE | IL0890200 | 37,983 | Ground water | 1 | Below the study levels |
| CARROLLTON, IL | IL0610050 | 2,513 | Ground water | 1 | Below the study levels |
| CARY | IL1110100 | 17,826 | Ground water | 6 | Below the study levels |
| CASEY | IL0230050 | 3,274 | Ground water purchased | 1 | Below the study levels |
| CASEYVILLE | IL1630250 | 13,798 | Surface water purchased | 1 | Below the study levels |
| CENTRALIA | IL1214220 | 12,182 | Surface water | 1 | Below the study levels |
| CHANNAHON | IL1970200 | 13,380 | Ground water | 3 | Reached a study level |
| CHARLESTON | IL0290100 | 17,286 | Surface water | 1 | Below the study levels |
| CHATHAM | IL1670300 | 16,423 | Ground water purchased | 1 | Below the study levels |
| CHERRY VALLEY | IL2010050 | 4,731 | Ground water | 4 | Below the study levels |
| CHESTER | IL1570100 | 8,407 | Surface water | 1 | Below the study levels |
| CHICAGO | IL0316000 | 2,721,308 | Surface water | 2 | Below the study levels |
| CHICAGO HEIGHTS | IL0310450 | 26,184 | Surface water purchased | 1 | Below the study levels |
| CHICAGO RIDGE | IL0310480 | 14,130 | Surface water purchased | 1 | Below the study levels |
| CHILLICOTHE | IL1430200 | 6,660 | Ground water | 7 | Below the study levels |
| CICERO | IL0310510 | 83,000 | Surface water purchased | 1 | Below the study levels |
| CLARK-EDGAR RWD | IL0230010 | 9,657 | Ground water | 1 | Below the study levels |
| CLEAR WATER SERVICE CORP | IL0295100 | 8,900 | Ground water | 2 | Below the study levels |
| CLINTON | IL0390050 | 7,200 | Ground water | 1 | Below the study levels |
| COAL CITY | IL0630200 | 5,749 | Ground water | 1 | Below the study levels |
| COAL VALLEY | IL1614260 | 3,873 | Ground water | 3 | Below the study levels |
| COAL VALLEY PWD | IL1995250 | 4,023 | Surface water purchased | 1 | Below the study levels |
| COLLINSVILLE, IL | IL1194280 | 29,500 | Ground water | 1 | Reached a study level |
| COLUMBIA | IL1330050 | 11,129 | Surface water purchased | 1 | Below the study levels |
| CORINTH PWD | IL1995120 | 3,927 | Surface water purchased | 1 | Below the study levels |
| CORTLAND | IL0370051 | 4,398 | Ground water | 4 | Below the study levels |
| COUNTRY CLUB HILLS | IL0310540 | 16,500 | Surface water purchased | 1 | Below the study levels |
| COUNTRYSIDE | IL0310570 | 6,420 | Surface water purchased | 1 | Below the study levels |
| CREST HILL | IL1970250 | 21,169 | Ground water | 7 | Reached a study level |
| CRETE | IL1970300 | 8,275 | Ground water | 5 | Below the study levels |
| CREVE COEUR | IL1790100 | 4,934 | Ground water | 1 | Below the study levels |
| CRYSTAL LAKE | IL1110150 | 40,661 | Ground water | 5 | Below the study levels |
| CURRAN-GARDNER TOWNSHIP PWD | IL1675350 | 6,651 | Ground water | 1 | Below the study levels |
| DALLAS RURAL WATER DISTRICT | IL0710010 | 6,370 | Ground water | 2 | Below the study levels |
| DARIEN | IL0430270 | 21,751 | Surface water purchased | 1 | Below the study levels |
| DE KALB | IL0370100 | 40,290 | Ground water | 5 | Below the study levels |
| DECATUR | IL1150150 | 76,122 | Surface water | 1 | Below the study levels |
| DEERFIELD | IL0974340 | 19,196 | Surface water purchased | 1 | Below the study levels |
| DES PLAINES | IL0310630 | 60,675 | Surface water purchased | 2 | Below the study levels |
| DIXMOOR | IL0310660 | 2,973 | Surface water purchased | 1 | Below the study levels |
| DIXON | IL1030200 | 15,096 | Ground water | 6 | Below the study levels |
| DOVER | IL0110350 | 200 | Ground water | 1 | Below the study levels |
| DUPO | IL1630350 | 4,684 | Ground water | 1 | Reached a study level |
| DUQUOIN | IL1450100 | 7,169 | Surface water purchased | 1 | Below the study levels |
| DWIGHT | IL1050250 | 4,400 | Ground water | 1 | Below the study levels |
| E J WATER COOP | IL0790010 | 29,720 | Surface water | 6 | Below the study levels |
| EAST ALTON | IL1190200 | 5,786 | Ground water | 1 | Reached a study level |
| EAST MOLINE | IL1610250 | 21,374 | Surface water | 1 | Below the study levels |
| EAST PEORIA | IL1790200 | 22,284 | Ground water | 6 | Below the study levels |
| EASTERN ILLINOIS UNIVERSITY | IL0295500 | 5,500 | Surface water purchased | 1 | Below the study levels |
| EDWARDSVILLE | IL1190250 | 26,808 | Ground water | 1 | Below the study levels |
| EFFINGHAM | IL0490250 | 12,252 | Surface water | 1 | Below the study levels |
| ELDORADO | IL1655030 | 4,715 | Ground water purchased | 1 | Below the study levels |
| ELK GROVE VILLAGE | IL0314400 | 31,802 | Surface water purchased | 1 | Below the study levels |
| ELMHURST | IL0430350 | 45,000 | Surface water purchased | 1 | Below the study levels |
| EMBARRAS AREA WATER DISTRICT | IL0290020 | 3,750 | Ground water purchased | 1 | Below the study levels |
| EUREKA | IL2030200 | 5,216 | Ground water | 1 | Below the study levels |
| EVANSTON | IL0310810 | 74,486 | Surface water | 1 | Below the study levels |
| EVERGREEN PARK | IL0310840 | 19,943 | Surface water purchased | 1 | Below the study levels |
| FAIRBURY | IL1050350 | 3,633 | Ground water | 1 | Below the study levels |
| FAIRFIELD | IL1910100 | 6,202 | Surface water | 1 | Below the study levels |
| FAYETTE WATER COMPANY | IL0510010 | 5,608 | Surface water purchased | 3 | Below the study levels |
| FLORA | IL0250100 | 5,233 | Surface water purchased | 1 | Below the study levels |
| FLOSSMOOR | IL0310870 | 9,371 | Surface water purchased | 1 | Below the study levels |
| FOREST PARK | IL0310900 | 14,340 | Surface water purchased | 1 | Below the study levels |
| FORSYTH, IL | IL1150200 | 3,490 | Ground water | 1 | Below the study levels |
| FORT MASSAC PWD | IL1275050 | 6,290 | Ground water purchased | 1 | Below the study levels |
| FOUNTAIN WATER DISTRICT | IL1330020 | 3,650 | Ground water | 1 | Below the study levels |
| FOX LAKE | IL0970200 | 11,780 | Ground water | 4 | Below the study levels |
| FOX RIVER GROVE | IL1110200 | 4,702 | Ground water | 2 | Below the study levels |
| FRANKFORT | IL1970400 | 24,000 | Ground water | 6 | Below the study levels |
| FRANKLIN PARK | IL0310960 | 18,467 | Surface water purchased | 1 | Below the study levels |
| FREEBURG | IL1630600 | 4,707 | Surface water purchased | 2 | Below the study levels |
| FREEPORT | IL1770200 | 23,930 | Ground water | 4 | Reached a study level |
| FULTON | IL1950250 | 3,346 | Ground water | 2 | Below the study levels |
| GALENA | IL0850200 | 3,308 | Ground water | 3 | Below the study levels |
| GALESBURG | IL0950200 | 31,620 | Ground water | 1 | Reached a study level |
| GENESEO | IL0730500 | 6,539 | Ground water | 1 | Below the study levels |
| GENEVA | IL0890350 | 21,247 | Ground water | 1 | Below the study levels |
| GENOA | IL0370150 | 5,298 | Ground water | 3 | Below the study levels |
| GEORGETOWN | IL1830350 | 4,200 | Ground water | 1 | Below the study levels |
| GIBSON CITY | IL0530100 | 3,500 | Ground water | 1 | Below the study levels |
| GILBERTS | IL0890400 | 8,366 | Ground water | 1 | Below the study levels |
| GILLESPIE | IL1170400 | 3,737 | Surface water | 1 | Below the study levels |
| GLEN CARBON | IL1190300 | 12,618 | Surface water purchased | 1 | Below the study levels |
| GLEN ELLYN | IL0430450 | 28,850 | Surface water purchased | 1 | Below the study levels |
| GLENCOE | IL0310990 | 8,849 | Surface water | 1 | Below the study levels |
| GLENDALE HEIGHTS | IL0430400 | 33,176 | Surface water purchased | 1 | Below the study levels |
| GLENVIEW | IL0311020 | 47,856 | Surface water purchased | 1 | Below the study levels |
| GLENWOOD | IL0311050 | 8,956 | Surface water purchased | 1 | Below the study levels |
| GRANDWOOD PARK SUBDIVISION - LAKE CO PW | IL0975600 | 5,751 | Surface water purchased | 1 | Below the study levels |
| GRAYSLAKE | IL0970250 | 21,248 | Surface water purchased | 1 | Below the study levels |
| GREAT LAKES NAVAL TRAINING STATION | IL0975227 | 23,000 | Surface water | 1 | Below the study levels |
| GREENVILLE | IL0050050 | 8,310 | Surface water | 1 | Below the study levels |
| GURNEE | IL0970350 | 30,193 | Surface water purchased | 1 | Below the study levels |
| HAINESVILLE | IL0970400 | 3,528 | Ground water | 2 | Below the study levels |
| HAMILTON COUNTY WATER DISTRICT | IL0651000 | 3,958 | Surface water purchased | 1 | Below the study levels |
| HAMPSHIRE | IL0890450 | 7,758 | Ground water | 2 | Below the study levels |
| HANOVER | IL0850250 | 863 | Ground water | 2 | Below the study levels |
| HANOVER PARK | IL0314480 | 37,470 | Surface water purchased | 1 | Below the study levels |
| HARRISBURG | IL1650200 | 8,524 | Ground water purchased | 1 | Below the study levels |
| HARVARD | IL1110250 | 9,469 | Ground water | 3 | Below the study levels |
| HARVEY | IL0311110 | 25,000 | Surface water purchased | 1 | Below the study levels |
| HARWOOD HEIGHTS | IL0311140 | 9,065 | Surface water purchased | 1 | Below the study levels |
| HAVANA | IL1250200 | 2,963 | Ground water | 1 | Below the study levels |
| HAZEL CREST | IL0311170 | 13,792 | Surface water purchased | 1 | Below the study levels |
| HERRIN | IL1990400 | 12,747 | Surface water purchased | 1 | Below the study levels |
| HICKORY HILLS | IL0311200 | 14,505 | Surface water purchased | 1 | Below the study levels |
| HIGHLAND | IL1190550 | 10,674 | Surface water | 1 | Below the study levels |
| HIGHLAND PARK, IL | IL0970500 | 30,176 | Surface water | 1 | Below the study levels |
| HIGHWOOD | IL0970550 | 5,335 | Surface water | 1 | Below the study levels |
| HILLSBORO | IL1350300 | 4,402 | Surface water | 1 | Below the study levels |
| HILLSIDE | IL0311230 | 8,200 | Surface water purchased | 1 | Below the study levels |
| HINSDALE | IL0434520 | 17,900 | Surface water purchased | 1 | Below the study levels |
| HOFFMAN ESTATES | IL0311290 | 50,179 | Surface water purchased | 1 | Below the study levels |
| HOMETOWN | IL0311320 | 4,240 | Surface water purchased | 1 | Below the study levels |
| HOMEWOOD | IL0311350 | 19,463 | Surface water purchased | 1 | Below the study levels |
| HOOPESTON | IL1830450 | 5,802 | Ground water | 1 | Below the study levels |
| HUNTLEY | IL1110350 | 28,495 | Ground water | 5 | Below the study levels |
| IL AMERICAN-ALTON | IL1195150 | 46,127 | Surface water | 1 | Below the study levels |
| IL AMERICAN-ANDALUSIA | IL1610050 | 1,184 | Ground water | 1 | Below the study levels |
| IL AMERICAN-CHAMPAIGN | IL0195300 | 150,000 | Ground water | 2 | Below the study levels |
| IL AMERICAN-CHICAGO SUBURBAN | IL0315150 | 11,187 | Surface water purchased | 1 | Below the study levels |
| IL AMERICAN-COUNTRY CLUB | IL0435350 | 1,014 | Surface water purchased | 1 | Below the study levels |
| IL AMERICAN-EAST ST LOUIS | IL1635040 | 131,368 | Surface water | 1 | Below the study levels |
| IL AMERICAN-FERNWAY | IL0315030 | 5,521 | Surface water purchased | 1 | Below the study levels |
| IL AMERICAN-GRANITE CITY | IL1195030 | 33,572 | Surface water | 1 | Below the study levels |
| IL AMERICAN-HOMER TOWNSHIP | IL1970100 | 24,543 | Surface water purchased | 1 | Below the study levels |
| IL AMERICAN-LIBERTY RIDGE WEST | IL0435650 | 3,307 | Surface water purchased | 1 | Below the study levels |
| IL AMERICAN-PEKIN | IL1795040 | 31,731 | Ground water | 7 | Below the study levels |
| IL AMERICAN-PEORIA | IL1435030 | 137,575 | Surface water | 4 | Reached a study level |
| IL AMERICAN-PONTIAC | IL1055030 | 11,864 | Surface water | 1 | Below the study levels |
| IL AMERICAN-SOUTH BELOIT | IL2010450 | 7,893 | Ground water purchased | 1 | Below the study levels |
| IL AMERICAN-STERLING | IL1955040 | 14,782 | Ground water | 2 | Below the study levels |
| IL AMERICAN-STREATOR | IL0995030 | 19,000 | Surface water | 1 | Below the study levels |
| IL AMERICAN-VALLEY VIEW | IL0437350 | 6,721 | Surface water purchased | 1 | Below the study levels |
| IL AMERICAN-WEST SUBURBAN | IL1974151 | 73,978 | Surface water purchased | 1 | Below the study levels |
| IL American - Lincoln | IL1075030 | 15,200 | Groundwater under influence of surface water | 3 | Reached a study level |
| ILLINOIS STATE UNIVERSITY-NORMAL | IL1135510 | 6,600 | Ground water purchased | 1 | Below the study levels |
| ISLAND LAKE | IL0974540 | 8,066 | Ground water | 2 | Below the study levels |
| ITASCA | IL0430500 | 9,506 | Surface water purchased | 3 | Below the study levels |
| JACKSONVILLE | IL1370200 | 19,903 | Surface water | 1 | Below the study levels |
| JERSEY RWC | IL0835300 | 12,750 | Surface water purchased | 1 | Below the study levels |
| JERSEYVILLE | IL0830250 | 8,412 | Ground water | 1 | Below the study levels |
| JOHNSTON CITY | IL1990500 | 3,509 | Surface water purchased | 1 | Below the study levels |
| JOLIET | IL1970450 | 160,000 | Ground water | 11 | Below the study levels |
| JUSTICE-WILLOW SPRINGS WATER COMMISSION | IL0315820 | 18,450 | Surface water purchased | 1 | Below the study levels |
| KENILWORTH | IL0311500 | 2,514 | Surface water purchased | 1 | Below the study levels |
| KINMUNDY | IL1210300 | 940 | Surface water purchased | 1 | Below the study levels |
| LA GRANGE HIGHLANDS SANITARY DISTRICT | IL0315860 | 6,600 | Surface water purchased | 1 | Below the study levels |
| LA GRANGE PARK | IL0311560 | 13,011 | Surface water purchased | 1 | Below the study levels |
| LA SALLE | IL0990300 | 9,700 | Ground water | 1 | Below the study levels |
| LAKE BLUFF | IL0970750 | 5,600 | Surface water purchased | 1 | Below the study levels |
| LAKE FOREST | IL0970800 | 19,642 | Surface water | 1 | Below the study levels |
| LAKE IN THE HILLS | IL1110400 | 28,661 | Ground water | 8 | Below the study levels |
| LAKE OF EGYPT PWD | IL1995200 | 11,368 | Surface water | 1 | Below the study levels |
| LAKE VILLA | IL0970840 | 8,829 | Surface water purchased | 1 | Below the study levels |
| LAKE WINDERMERE ESTATES SUBDIVISION | IL1795730 | 300 | Ground water | 2 | Below the study levels |
| LAKE ZURICH | IL0970850 | 19,759 | Ground water | 5 | Below the study levels |
| LAWRENCEVILLE | IL1010150 | 4,524 | Ground water | 1 | Below the study levels |
| LCPW - PEKARA SUBDIVISION | IL0975900 | 3,711 | Surface water purchased | 5 | Below the study levels |
| LE ROY | IL1130750 | 3,498 | Ground water | 1 | Below the study levels |
| LEBANON | IL1630650 | 4,714 | Surface water purchased | 1 | Below the study levels |
| LEMONT | IL0311620 | 17,500 | Ground water | 4 | Below the study levels |
| LEYDEN TWSP WATER DISTRICT | IL0315880 | 10,000 | Surface water purchased | 1 | Below the study levels |
| LIBERTYVILLE | IL0970900 | 20,500 | Surface water purchased | 1 | Below the study levels |
| LINCOLNSHIRE | IL0970950 | 7,940 | Surface water purchased | 1 | Below the study levels |
| LINCOLNWOOD | IL0311650 | 13,463 | Surface water purchased | 1 | Below the study levels |
| LINDENHURST | IL0971000 | 14,500 | Surface water purchased | 1 | Below the study levels |
| LISLE | IL0430551 | 24,223 | Surface water purchased | 1 | Below the study levels |
| LITCHFIELD | IL1350400 | 6,648 | Surface water | 1 | Below the study levels |
| LOCKPORT | IL1970500 | 23,100 | Ground water | 7 | Below the study levels |
| LOMBARD | IL0430600 | 44,476 | Surface water purchased | 1 | Below the study levels |
| LONG CREEK TOWNSHIP PWS | IL1155150 | 7,850 | Ground water | 1 | Below the study levels |
| LOVES PARK | IL2010150 | 23,335 | Ground water | 4 | Below the study levels |
| LOW POINT WATER DISTRICT | IL2035100 | 200 | Ground water | 1 | Below the study levels |
| LYNWOOD | IL0311680 | 9,149 | Surface water purchased | 1 | Below the study levels |
| LYONS, IL | IL0311710 | 10,304 | Surface water purchased | 1 | Below the study levels |
| MACOMB | IL1090350 | 15,051 | Surface water | 1 | Below the study levels |
| MAHOMET | IL0190450 | 6,580 | Ground water | 1 | Below the study levels |
| MARENGO | IL1110650 | 7,572 | Ground water | 2 | Below the study levels |
| MARION | IL1990550 | 16,855 | Surface water purchased | 1 | Below the study levels |
| MARKHAM | IL0311770 | 12,500 | Surface water purchased | 1 | Below the study levels |
| MARSEILLES | IL0990500 | 5,061 | Ground water | 2 | Below the study levels |
| MARSHALL | IL0230100 | 3,947 | Ground water | 1 | Below the study levels |
| MARYVILLE | IL1190750 | 10,150 | Ground water | 1 | Below the study levels |
| MASCOUTAH | IL1630800 | 8,759 | Surface water purchased | 1 | Below the study levels |
| MATTESON | IL0311800 | 18,293 | Surface water purchased | 1 | Below the study levels |
| MATTOON | IL0290250 | 19,500 | Surface water | 1 | Below the study levels |
| MAYWOOD | IL0311830 | 24,090 | Surface water purchased | 1 | Below the study levels |
| MCHENRY | IL1110600 | 22,335 | Ground water | 4 | Below the study levels |
| MELROSE PARK | IL0311860 | 24,206 | Surface water purchased | 1 | Below the study levels |
| MENDON | IL0010500 | 953 | Ground water purchased | 1 | Below the study levels |
| MENDOTA | IL0990550 | 7,100 | Ground water | 3 | Below the study levels |
| METAMORA | IL2030350 | 3,895 | Ground water | 1 | Below the study levels |
| METROPOLIS | IL1270150 | 6,309 | Ground water | 1 | Below the study levels |
| MIDLOTHIAN | IL0311920 | 14,819 | Surface water purchased | 1 | Below the study levels |
| MILAN | IL1610400 | 4,945 | Ground water | 2 | Below the study levels |
| MILL CREEK PWD | IL0015300 | 5,755 | Ground water | 1 | Below the study levels |
| MILL CREEK WATER RECLAMATION DISTRICT | IL0890120 | 8,000 | Ground water | 1 | Below the study levels |
| MILLSTADT | IL1630850 | 4,071 | Surface water purchased | 1 | Below the study levels |
| MILLSTONE PWD | IL1515050 | 5,565 | Ground water | 1 | Below the study levels |
| MINOOKA | IL0630550 | 12,800 | Ground water | 3 | Below the study levels |
| MITCHELL PWD | IL1195210 | 5,253 | Surface water purchased | 1 | Below the study levels |
| MOKENA | IL1970600 | 19,887 | Surface water purchased | 1 | Below the study levels |
| MOLINE | IL1610450 | 44,500 | Surface water | 1 | Below the study levels |
| MONEE | IL1970650 | 5,148 | Ground water | 3 | Below the study levels |
| MONMOUTH | IL1870150 | 8,902 | Ground water | 2 | Below the study levels |
| MONTGOMERY | IL0894690 | 28,956 | Ground water | 3 | Below the study levels |
| MONTICELLO | IL1470350 | 5,548 | Ground water | 1 | Below the study levels |
| MORO PWD | IL1195250 | 723 | Ground water purchased | 1 | Below the study levels |
| MORRIS, IL | IL0630600 | 14,775 | Ground water | 1 | Below the study levels |
| MORRISON | IL1950350 | 4,188 | Ground water | 2 | Below the study levels |
| MORTON | IL1790500 | 17,111 | Ground water | 3 | Below the study levels |
| MORTON GROVE | IL0311950 | 25,297 | Surface water purchased | 1 | Below the study levels |
| MOUNT CARMEL | IL1850200 | 7,015 | Groundwater under influence of surface water | 1 | Below the study levels |
| MOUNT OLIVE | IL1170700 | 2,193 | Surface water purchased | 1 | Below the study levels |
| MOUNT PROSPECT | IL0311980 | 41,000 | Surface water purchased | 1 | Below the study levels |
| MOUNT VERNON | IL0810300 | 15,793 | Surface water purchased | 1 | Below the study levels |
| MOUNT ZION | IL1150350 | 5,833 | Surface water purchased | 1 | Below the study levels |
| MUNDELEIN | IL0971150 | 31,500 | Surface water purchased | 1 | Below the study levels |
| MURDALE PWD | IL0775200 | 4,963 | Surface water purchased | 1 | Below the study levels |
| NAPERVILLE | IL0434670 | 156,406 | Surface water purchased | 1 | Below the study levels |
| NASHVILLE | IL1890300 | 3,230 | Surface water | 1 | Below the study levels |
| NEW BADEN | IL0274700 | 4,178 | Surface water purchased | 1 | Below the study levels |
| NEW LENOX | IL1970700 | 27,690 | Surface water purchased | 1 | Below the study levels |
| NILES, IL | IL0312010 | 29,350 | Surface water purchased | 1 | Below the study levels |
| NORMAL | IL1130900 | 52,736 | Ground water | 1 | Below the study levels |
| NORRIDGE | IL0312040 | 15,251 | Surface water purchased | 1 | Below the study levels |
| NORTH AURORA | IL0890600 | 18,261 | Ground water | 2 | Below the study levels |
| NORTH CHICAGO | IL0971250 | 16,813 | Surface water | 1 | Below the study levels |
| NORTH EAST CENTRAL PWD | IL1195280 | 3,975 | Ground water purchased | 1 | Below the study levels |
| NORTH EAST MARION COUNTY WATER CMPNY | IL1210030 | 3,220 | Surface water purchased | 1 | Below the study levels |
| NORTH PARK PWD | IL2015500 | 35,580 | Ground water | 3 | Reached a study level |
| NORTH RIVERSIDE | IL0312160 | 7,071 | Surface water purchased | 1 | Below the study levels |
| NORTHBROOK | IL0312070 | 34,407 | Surface water | 1 | Below the study levels |
| NORTHEAST MOUNT VERNON WATER COMPANY | IL0810010 | 5,483 | Surface water purchased | 1 | Below the study levels |
| NORTHERN ILLINOIS UNIVERSITY-DEKALB | IL0375500 | 6,500 | Ground water purchased | 3 | Below the study levels |
| NORTHFIELD, IL | IL0312100 | 5,470 | Surface water purchased | 1 | Below the study levels |
| NORTHLAKE | IL0314710 | 12,840 | Surface water purchased | 1 | Below the study levels |
| O FALLON | IL1631100 | 46,603 | Surface water purchased | 1 | Below the study levels |
| OAK BROOK | IL0430700 | 9,400 | Surface water purchased | 1 | Below the study levels |
| OAK FOREST | IL0312190 | 27,478 | Surface water purchased | 1 | Below the study levels |
| OAK LAWN | IL0312220 | 58,362 | Surface water purchased | 1 | Below the study levels |
| OAK PARK, IL | IL0312250 | 54,583 | Surface water purchased | 1 | Below the study levels |
| OGLESBY | IL0990700 | 4,500 | Ground water | 1 | Below the study levels |
| OLNEY | IL1590200 | 8,877 | Surface water | 1 | Below the study levels |
| OLYMPIA FIELDS | IL0312280 | 4,922 | Surface water purchased | 1 | Below the study levels |
| OREGON | IL1410400 | 3,449 | Ground water | 4 | Below the study levels |
| ORLAND PARK | IL0312310 | 58,020 | Surface water purchased | 1 | Below the study levels |
| OSWEGO | IL0930150 | 38,169 | Ground water | 8 | Below the study levels |
| OTTAWA | IL0990800 | 18,097 | Ground water | 2 | Below the study levels |
| PALATINE | IL0312340 | 70,875 | Surface water purchased | 1 | Below the study levels |
| PALOS HEIGHTS | IL0312370 | 15,500 | Surface water purchased | 1 | Below the study levels |
| PALOS HILLS | IL0312400 | 18,530 | Surface water purchased | 1 | Below the study levels |
| PALOS PARK | IL0311000 | 4,873 | Surface water purchased | 1 | Below the study levels |
| PANA | IL0210500 | 5,800 | Surface water | 1 | Below the study levels |
| PARIS | IL0450300 | 9,100 | Ground water | 1 | Below the study levels |
| PARK CITY | IL0971400 | 5,425 | Surface water purchased | 1 | Below the study levels |
| PARK FOREST | IL0314740 | 21,687 | Ground water | 1 | Below the study levels |
| PARK RIDGE | IL0312460 | 39,800 | Surface water purchased | 1 | Below the study levels |
| PAXTON | IL0530250 | 4,200 | Ground water | 1 | Below the study levels |
| PEORIA HEIGHTS | IL1434750 | 5,908 | Ground water | 1 | Below the study levels |
| PERU | IL0990850 | 10,300 | Ground water | 1 | Below the study levels |
| PETERSBURG | IL1290200 | 4,725 | Ground water | 1 | Below the study levels |
| PIKE COUNTY PWD 1 | IL1495000 | 5,375 | Ground water | 2 | Below the study levels |
| PINGREE GROVE | IL0890160 | 10,365 | Ground water | 1 | Below the study levels |
| PITTSFIELD | IL1490750 | 4,697 | Ground water | 1 | Below the study levels |
| PLAINFIELD | IL1970800 | 50,000 | Surface water purchased | 1 | Below the study levels |
| PLANO | IL0930200 | 12,600 | Ground water | 3 | Below the study levels |
| PLEASANT VALLEY PWD | IL1435470 | 3,783 | Ground water | 3 | Below the study levels |
| PONTOON BEACH PWD | IL1195300 | 3,325 | Surface water purchased | 1 | Below the study levels |
| POPLAR GROVE WEST-COUNTRYSIDE | IL0070350 | 790 | Ground water | 1 | Below the study levels |
| POSEN | IL0312520 | 5,331 | Surface water purchased | 1 | Below the study levels |
| PRINCETON | IL0110850 | 7,832 | Ground water | 1 | Below the study levels |
| Prairie Path Water Co. - Clarendon | IL0435300 | 625 | Ground water | 1 | Below the study levels |
| Prairie Path Water Co. - Lake Holiday | IL0995200 | 4,750 | Ground water | 1 | Below the study levels |
| Prairie Path Water Co. - Whispering Hills | IL1115700 | 8,300 | Ground water | 5 | Reached a study level |
| QUINCY | IL0010650 | 42,000 | Surface water | 1 | Below the study levels |
| RACCOON WATER COMPANY | IL1215100 | 7,080 | Surface water purchased | 3 | Below the study levels |
| RANTOUL | IL0190650 | 13,000 | Ground water | 1 | Below the study levels |
| RED BUD | IL1570450 | 3,804 | Ground water | 1 | Below the study levels |
| RICHTON PARK | IL0312550 | 12,504 | Ground water | 3 | Below the study levels |
| RIVER FOREST | IL0312610 | 11,717 | Surface water purchased | 1 | Below the study levels |
| RIVER GROVE | IL0312640 | 10,282 | Surface water purchased | 1 | Below the study levels |
| RIVERSIDE | IL0312670 | 9,298 | Surface water purchased | 1 | Below the study levels |
| RIVERTON | IL1670950 | 4,279 | Ground water | 1 | Below the study levels |
| RIVERWOODS | IL0971450 | 3,618 | Surface water purchased | 1 | Below the study levels |
| ROBBINS | IL0312700 | 5,415 | Surface water purchased | 1 | Below the study levels |
| ROBINSON-PALESTINE WATER COMMISSION | IL0335030 | 11,331 | Ground water | 1 | Below the study levels |
| ROCHELLE | IL1410500 | 9,446 | Ground water | 5 | Below the study levels |
| ROCHESTER | IL1671000 | 3,856 | Surface water purchased | 1 | Below the study levels |
| ROCK ISLAND | IL1610650 | 39,018 | Surface water | 1 | Below the study levels |
| ROCK ISLAND ARSENAL, US ARMY | IL1615387 | 7,800 | Surface water | 1 | Below the study levels |
| ROCKFORD, IL | IL2010300 | 147,051 | Ground water | 23 | Below the study levels |
| ROCKTON | IL2010350 | 7,685 | Ground water | 4 | Below the study levels |
| ROLLING MEADOWS | IL0312730 | 23,329 | Surface water purchased | 1 | Below the study levels |
| ROMEOVILLE | IL1970900 | 50,458 | Ground water | 8 | Below the study levels |
| ROSELLE | IL0434820 | 22,897 | Surface water purchased | 1 | Below the study levels |
| ROUND LAKE BEACH | IL0971550 | 27,200 | Surface water purchased | 1 | Below the study levels |
| ROUND LAKE PARK | IL0971600 | 4,900 | Surface water purchased | 2 | Below the study levels |
| SALEM | IL1210450 | 7,905 | Surface water | 1 | Below the study levels |
| SALINE VALLEY CONSERVANCY DISTRICT | IL1655300 | 3,921 | Ground water | 2 | Below the study levels |
| SANDWICH | IL0374850 | 7,156 | Ground water | 2 | Below the study levels |
| SANGAMON VALLEY PWD | IL0195150 | 5,300 | Ground water | 1 | Below the study levels |
| SCHAUMBURG | IL0314890 | 75,750 | Surface water purchased | 1 | Below the study levels |
| SCHILLER PARK | IL0312850 | 11,709 | Surface water purchased | 1 | Below the study levels |
| SHADY OAKS MHP | IL0635225 | 912 | Ground water | 1 | Below the study levels |
| SHELBYVILLE | IL1730300 | 5,600 | Ground water | 1 | Below the study levels |
| SHOREWOOD, IL | IL1975080 | 18,645 | Ground water | 5 | Below the study levels |
| SILVIS | IL1610700 | 7,473 | Surface water purchased | 1 | Below the study levels |
| SOUTH ELGIN | IL0890800 | 23,648 | Ground water | 8 | Reached a study level |
| SOUTH HIGHWAY PWD | IL0775400 | 4,972 | Surface water purchased | 1 | Below the study levels |
| SOUTH HOLLAND | IL0312970 | 22,000 | Surface water purchased | 2 | Below the study levels |
| SOUTH JACKSONVILLE | IL1370400 | 3,501 | Ground water | 2 | Below the study levels |
| SOUTHERN IL UNIVERSITY-EDWARDSVILLE | IL1195550 | 2,817 | Ground water purchased | 1 | Below the study levels |
| SPRING VALLEY | IL0111000 | 5,582 | Ground water | 1 | Below the study levels |
| SPRINGFIELD, IL | IL1671200 | 117,444 | Surface water | 1 | Below the study levels |
| ST CHARLES | IL0894830 | 33,103 | Ground water | 5 | Below the study levels |
| STAUNTON | IL1171050 | 5,756 | Surface water | 1 | Below the study levels |
| STEGER | IL0314860 | 9,700 | Ground water | 2 | Below the study levels |
| STICKNEY | IL0313000 | 6,902 | Surface water purchased | 1 | Below the study levels |
| STONE PARK | IL0313030 | 4,576 | Surface water purchased | 1 | Below the study levels |
| STREAMWOOD | IL0313060 | 39,577 | Surface water purchased | 1 | Below the study levels |
| SUGAR GROVE | IL0890850 | 11,243 | Ground water | 5 | Below the study levels |
| SULLIVAN | IL1390300 | 4,729 | Ground water | 1 | Below the study levels |
| SUMMIT | IL0310060 | 11,161 | Surface water purchased | 1 | Below the study levels |
| SYCAMORE | IL0370550 | 18,500 | Ground water | 5 | Below the study levels |
| TAYLORVILLE | IL0210600 | 12,806 | Surface water | 1 | Below the study levels |
| TINLEY PARK | IL0314910 | 56,703 | Surface water purchased | 1 | Below the study levels |
| TRITOWNSHIP WATER DISTRICT | IL1190080 | 3,470 | Surface water purchased | 1 | Below the study levels |
| TROY, IL | IL1191000 | 16,962 | Ground water | 1 | Below the study levels |
| TUSCOLA | IL0415030 | 4,875 | Ground water purchased | 1 | Below the study levels |
| U OF I-CHAMPAIGN | IL0195500 | 13,000 | Ground water purchased | 1 | Below the study levels |
| UTL INC-GALENA TERRITORY | IL0855050 | 2,294 | Ground water | 6 | Below the study levels |
| VALMEYER | IL1330250 | 1,263 | Ground water purchased | 1 | Below the study levels |
| VANDALIA | IL0510350 | 7,616 | Surface water | 1 | Below the study levels |
| VANDALIA CORRECTIONAL CENTER | IL0515500 | 700 | Surface water purchased | 1 | Below the study levels |
| VERNON HILLS - LAKE CO PW | IL0971750 | 33,207 | Surface water purchased | 1 | Below the study levels |
| VILLA PARK | IL0430800 | 22,263 | Surface water purchased | 1 | Below the study levels |
| VIRDEN | IL1171100 | 3,274 | Surface water purchased | 1 | Below the study levels |
| VOLO | IL0971770 | 6,629 | Surface water purchased | 1 | Below the study levels |
| WARRENVILLE | IL0430833 | 12,350 | Ground water | 4 | Below the study levels |
| WASCO SD | IL0890110 | 4,000 | Ground water | 1 | Below the study levels |
| WASHINGTON COUNTY WATER COMPANY | IL1895600 | 11,374 | Surface water purchased | 4 | Below the study levels |
| WASHINGTON, IL | IL1790750 | 14,793 | Ground water | 2 | Below the study levels |
| WATERLOO | IL1330300 | 10,190 | Ground water | 1 | Below the study levels |
| WAUCONDA | IL0971850 | 15,349 | Surface water purchased | 1 | Below the study levels |
| WAUKEGAN | IL0971900 | 87,149 | Surface water | 1 | Below the study levels |
| WEE-MA-TUK WATER DISTRICT | IL0570040 | 863 | Purchased ground water under influence of surface water source | 1 | Below the study levels |
| WEST CHICAGO | IL0430900 | 25,166 | Ground water | 1 | Below the study levels |
| WEST DUNDEE | IL0890950 | 7,845 | Ground water | 2 | Below the study levels |
| WEST FRANKFORT | IL0550700 | 8,650 | Surface water purchased | 1 | Below the study levels |
| WESTERN SPRINGS | IL0313180 | 13,274 | Ground water | 1 | Below the study levels |
| WESTVILLE | IL1830950 | 3,917 | Surface water purchased | 1 | Below the study levels |
| WHEATON | IL0431050 | 53,970 | Surface water purchased | 1 | Below the study levels |
| WHEELING | IL0314970 | 39,725 | Surface water purchased | 1 | Below the study levels |
| WILDWOOD SUBDIVISION - LAKE CO PW | IL0977350 | 14,832 | Surface water purchased | 1 | Below the study levels |
| WILLIAMSVILLE | IL1671300 | 6,198 | Surface water purchased | 1 | Below the study levels |
| WILLOW LAKE ESTATES MHP | IL0894400 | 920 | Surface water purchased | 1 | Below the study levels |
| WILLOWBROOK | IL0431100 | 9,000 | Surface water purchased | 1 | Below the study levels |
| WILMETTE | IL0313300 | 27,087 | Surface water | 1 | Below the study levels |
| WINFIELD | IL0431150 | 9,835 | Surface water purchased | 1 | Below the study levels |
| WINNETKA | IL0313330 | 12,475 | Surface water | 1 | Below the study levels |
| WINTHROP HARBOR | IL0971950 | 6,565 | Surface water purchased | 1 | Below the study levels |
| WONDER LAKE | IL1115750 | 3,870 | Ground water | 3 | Below the study levels |
| WOOD DALE | IL0431200 | 14,012 | Surface water purchased | 1 | Below the study levels |
| WOODHAVEN, IL | IL1035100 | 4,100 | Ground water | 1 | Below the study levels |
| WOODLAWN | IL0810450 | 3,587 | Surface water purchased | 1 | Below the study levels |
| WOODRIDGE | IL0431250 | 33,566 | Surface water purchased | 1 | Below the study levels |
| WOODSTOCK, IL | IL1110950 | 25,630 | Ground water | 2 | Below the study levels |
| WORTH | IL0313360 | 10,970 | Surface water purchased | 1 | Below the study levels |
| XENIA | IL0250300 | 542 | Surface water purchased | 1 | Below the study levels |
| YORKVILLE | IL0930250 | 23,000 | Ground water | 3 | Below the study levels |
| ZION | IL0972000 | 24,442 | Surface water purchased | 1 | Below the study levels |
How the count works
What is included
Each active community water system with complete monitoring is counted once, even if it is linked with several ZIP codes. Private wells are excluded, and UCMR 5 did not comprehensively monitor every small system. This page does not apply Illinois's state-specific standards or determine compliance. Use the official state or territory drinking-water program for current regulatory information.