Mchenry, IL
A PlainEnviro-computed score from reported facility/violation counts, not an official EPA rating, health forecast, or population-adjusted rate. See methodology.
Environmental data for Mchenry in Illinois · Population: 311,366
Mchenry, IL is tracked across three EPA datasets covering 32 Toxics Release Inventory (TRI) facilities, 38 Safe Drinking Water Act systems, and 0 Superfund National Priorities List sites. Together these generate an environmental burden score of 58/100 (Moderate Risk), calibrated against national distributions for facility density, chemical release volume, Superfund concentration, and water-system health violations.
Industrial disclosures inside the county total 1.1M lbs of reported toxic releases under EPCRA Section 313, while 15 water systems carry an active health-based violation in the SDWIS record. EPA Air Quality System monitors logged a median AQI of 43 and a peak AQI of 108 in 2024, with 67% of observed days rated "Good" (0–50).
All figures below draw directly from federal EPA records, TRI self-reported emissions, SDWIS compliance history, NPL Hazard Ranking System scores, and AQS daily AQI summaries, and are not adjusted, weighted, or forecast. A past violation or elevated score does not itself indicate current unsafe conditions; it documents the regulatory and disclosure history publicly filed with the U.S. Environmental Protection Agency through the most recent reporting cycle.
Air Quality History (2020–2024)
EPA Air Quality Index (AQI) data showing how many days per year fall into each air quality category.
| Year | Good | Moderate | Unhealthy (SG) | Max AQI |
|---|---|---|---|---|
| 2024 | 245 (67%) | 120 | 1 | 108 |
| 2023 | 191 (52%) | 153 | 16 | 230 |
| 2022 | 199 (55%) | 163 | 3 | 126 |
| 2021 | 187 (52%) | 174 | 2 | 105 |
| 2020 | 192 (57%) | 133 | 9 | 147 |
Source: EPA Air Quality System (AQS) Annual AQI by County EPA Air Quality System (AQS) Annual AQI by County AQI categories: Good (0-50), Moderate (51-100), Unhealthy for Sensitive Groups (101-150), Unhealthy (151-200), Very Unhealthy (201-300), Hazardous (301+)
For real-time air quality readings and pollutant breakdowns in Illinois, see the EPA's AirNow.gov.
Water Systems (38)
| System | Population | Violations |
|---|---|---|
| CRYSTAL LAKE | 40,661 | 0 |
| ALGONQUIN | 30,700 | 2 |
| LAKE IN THE HILLS | 28,661 | 0 |
| HUNTLEY | 28,495 | 1 |
| WOODSTOCK | 25,630 | 1 |
| MCHENRY | 22,335 | 1 |
| CARY | 17,826 | 1 |
| HARVARD | 9,469 | 1 |
| PRAIRIE PATH WATER CO-WHISPERING HILLS | 8,300 | 1 |
| MARENGO | 7,572 | 0 |
| FOX RIVER GROVE | 4,702 | 2 |
| LAKEWOOD | 4,267 | 0 |
| WONDER LAKE | 3,870 | 3 |
| LAKEMOOR | 2,720 | 0 |
| RICHMOND | 2,087 | 0 |
| WONDER LAKE (NIU) | 1,950 | 0 |
| PRAIRIE PATH WATER COMPANY-OAKWOOD | 1,600 | 2 |
| PRAIRIE PATH WATER COMPANY-WESTLAKE | 1,493 | 0 |
| HEBRON | 1,368 | 2 |
| PRAIRIE PATH WATER COMPANY-KILLARNEY | 1,232 | 0 |
| JOHNSBURG NO.2 | 1,124 | 3 |
| PRAIRIE PATH WATER COMPANY-HARBOR RIDGE | 1,064 | 0 |
| PRAIRIE PATH WATER COMPANY-LAKE MARIAN | 1,022 | 1 |
| PRAIRIE PATH WATER COMPANY-COVENTRY HILL | 882 | 0 |
| PRAIRIE PATH WATER COMPANY-HOLIDAY HILLS | 868 | 0 |
| PRAIRIE PATH WATER COMPANY-WALK UP WOODS | 775 | 1 |
| PRAIRIE PATH WATER COMPANY-NORTHERN HILL | 600 | 0 |
| UNION | 594 | 0 |
| PRAIRIE PATH WATER COMPANY-WILDWOOD | 490 | 0 |
| PRAIRIE PATH WATER CO-COVENTRY CREEK | 388 | 0 |
| PRAIRIE PATH WATER COMPANY-DEL-MAR | 300 | 2 |
| PRAIRIE PATH WATER COMPANY-ROCKVALE | 298 | 0 |
| PORTS SULLIVAN LAKE OWNERS ASSOCIATION | 293 | 0 |
| PRAIRIE PATH WATER COMPANY-VALENTINE | 252 | 0 |
| POWERS WATER CO, INC. | 216 | 0 |
| PRAIRIE PATH WATER COMPANY-CHAR-MAR | 186 | 0 |
| JOHNSBURG 1 | 174 | 0 |
| PRAIRIE PATH -PORT BARRINGTON SHORES | 67 | 0 |
TRI Facilities (32)
Cities in Mchenry (15)
Frequently Asked Questions
What is the environmental risk level in Mchenry, Illinois? ▼
Are there Superfund sites in Mchenry? ▼
How many toxic release facilities are in Mchenry? ▼
What is the air quality in Mchenry? ▼
Is the drinking water safe in Mchenry? ▼
What environmental agencies cover Mchenry? ▼
What does this county environmental profile show?
This county environmental profile rolls up EPA Toxics Release Inventory facility reports, Safe Drinking Water Information System public-water-system filings, and Superfund National Priorities List sites for the county boundary defined by the U.S. Census Bureau. Facility counts reflect facilities with a reporting address inside the county, not where downstream environmental effects may be observed. Population figures are from the most recent Census ACS 5-year estimate. The county detail page is updated whenever the upstream EPA programs publish revised data; see the methodology page for the documented ingest cadence and the editorial choices governing how aggregations are computed.
Read our methodology - how this data is sourced, computed, and verified.