County · Illinois
McHenry County, Illinois: drinking water records
This overview covers 18 ZIP codes and 33 community water systems in McHenry County. It also stands in for 1 ZIP codes whose utility has too little EPA data for a page of its own.
System population figures are summed from EPA registry records and can overlap where wholesalers and retail systems serve the same people. They are not a Census county-population estimate.
Water systems with the most complete records
| Water system | People served | PFAS survey results | PFAS found | Health-based violations | Lead, 9 in 10 homes at or below |
|---|---|---|---|---|---|
| Huntley IL1110350 | 28,495 | 300 | 0 | 1 | 1 ppb |
| Woodstock IL1110950 | 25,630 | 120 | 0 | 1 | 7 ppb |
| Prairie Path Water Co-Whispering Hills IL1115700 | 8,300 | 300 | 7 | 1 | 0 ppb |
| Fox River Grove IL1110200 | 4,702 | 120 | 4 | 1 | 7.2 ppb |
| Wonder Lake IL1115750 | 3,870 | 180 | 0 | 1 | 1.8 ppb |
| Crystal Lake IL1110150 | 40,661 | 300 | 2 | 0 | 7.7 ppb |
| Algonquin IL1110050 | 30,700 | 240 | 0 | 0 | 2.3 ppb |
| Lake in the Hills IL1110400 | 28,661 | 480 | 0 | 0 | 2.7 ppb |
| Mchenry IL1110600 | 22,335 | 240 | 1 | 0 | 4.1 ppb |
| Cary IL1110100 | 17,826 | 330 | 5 | 0 | 4.1 ppb |
| Harvard IL1110250 | 9,469 | 180 | 0 | 0 | 1.4 ppb |
| Marengo IL1110650 | 7,572 | 120 | 1 | 0 | 0 ppb |
| Lakewood IL1115760 | 4,267 | 0 | 0 | 0 | 1.5 ppb |
| Richmond IL1110750 | 2,089 | 0 | 0 | 0 | 8.7 ppb |
| Wonder Lake (Niu) IL1115850 | 1,950 | 0 | 0 | 0 | 0 ppb |
| Aqua Illinois-Mchenry Shores IL1115020 | 1,862 | 0 | 0 | 0 | 3.3 ppb |
| Hebron IL1110300 | 1,368 | 0 | 0 | 0 | 4.5 ppb |
| Prairie Path Water Company-Killarney IL1115400 | 1,232 | 0 | 0 | 0 | 2.4 ppb |
| Johnsburg No.2 IL1115080 | 1,124 | 0 | 0 | 0 | 0 ppb |
| Oakbrook Estates MHP IL1115125 | 1,012 | 0 | 0 | 0 | 0 ppb |
| Prairie Path Water Company-Holiday Hills IL1115350 | 868 | 0 | 0 | 0 | 2.7 ppb |
| Aqua Illinois-Crystal Clear Water Co. IL1115150 | 855 | 0 | 0 | 0 | 4.7 ppb |
| Prairie Path Water Company-Walk Up Woods IL1115800 | 775 | 0 | 0 | 0 | 3.3 ppb |
| Aqua Illinois-Eastwood Manor IL1115250 | 728 | 0 | 0 | 0 | 0 ppb |
| Il American-Terra Cotta IL1110080 | 681 | 0 | 0 | 0 | 1 ppb |
ZIP reports in McHenry County
No ZIP report in this county is published yet.
These ZIP codes are covered by this overview because their utility has too little EPA data for a separate page: 60072.
Sources and scope
EPA UCMR 5 occurrence data, samples collected 2023-01-03 – 2026-06-17, final release, August 2026 (file dated Aug 28, 2026); EPA SDWIS via ECHO, 2026Q2 extract (file dated Jul 9, 2026); EPA service-area boundaries v3.0; Census 2020 ZCTAs. Page generated 2026-09-03.
Counts cover the systems that report this county to EPA. A water system may cross county lines. "Found" means at least one result at or above the laboratory reporting level; it is not a compliance finding.