Public water system · IL1110600
ActiveMchenry
At a glance
Mchenry (PWSID IL1110600) is an active community water system in McHenry County, Illinois. It reports serving 22,335 people through 8,484 service connections. Its primary water source is groundwater, and EPA lists it as owned by a local government. Of the 12 most recent violations in EPA's records, none is health-based, and the most recent began in July 2025.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
22,335
Service connections
8,484
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Mchenry compare with other water systems in McHenry County?
By EPA's size categories, Mchenry is a large system (10,001 to 100,000 people). McHenry County has 192 active public water systems, and Mchenry is the 6th-largest of them by population served. Its population served is about 17 times the county average of 1,331 people per system, and accounts for 8.7% of the 255,516 people reported by systems filed under the county. Across Illinois, the 3,872 active systems average 3,204 people each. Nationally, the average active community water system reports serving 6,703 people, so Mchenry is about 3.3 times that figure.
What does “community water system” mean?
A community water system serves at least 15 connections used by year-round residents, or regularly serves at least 25 year-round residents. Homes, apartments and mobile-home parks are served by these. Illinois has 1,773 active community water systems, 46% of the state's 3,872 active systems. Groundwater means the system draws its water from wells or springs fed by underground aquifers. 2,808 Illinois systems (73%) list groundwater as their primary source.
Who owns and regulates Mchenry?
EPA lists Mchenry as owned by a local government. The IL state drinking water program is its primacy agency, the regulator with primary enforcement responsibility for the system under the Safe Drinking Water Act. 35 of the 192 active systems in McHenry County (18%) are also owned by a local government.
Does Mchenry have drinking water violations?
Of the 12 most recent violations in EPA's records, none is health-based, and the most recent began in July 2025. The violations listed here began between January 2023 and July 2025. By type: 12 monitoring and reporting. The contaminant or rule involved most often is Lead and Copper Rule (2 of them). EPA lists 12 as resolved. Resolved means at least one resolving action is on record: the system returned to compliance, the rule no longer applies, or no further action was needed.
| Began | Violation | Contaminant or rule | Health-based | Status |
|---|---|---|---|---|
| 2025-07-01 | Monitoring and reportingFollow-up Or Routine LCR Tap M/R · code 52 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2023-10-01 | Monitoring and reportingFollow-up Or Routine LCR Tap M/R · code 52 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2023-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | p-Dichlorobenzenecode 2969 | No | Resolved |
| 2023-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | 1,2,4-Trichlorobenzenecode 2378 | No | Resolved |
| 2023-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Benzenecode 2990 | No | Resolved |
| 2023-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Styrenecode 2996 | No | Resolved |
| 2023-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Trichloroethylenecode 2984 | No | Resolved |
| 2023-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Dichloromethanecode 2964 | No | Resolved |
| 2023-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Xylenes, Totalcode 2955 | No | Resolved |
| 2023-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Vinyl chloridecode 2976 | No | Resolved |
| 2023-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Carbon tetrachloridecode 2982 | No | Resolved |
| 2023-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | o-Dichlorobenzenecode 2968 | No | Resolved |
The 12 most recent violations in EPA's records, newest first.Labels and codes come from EPA's SDWIS reference tables. A monitoring or reporting violation means a required test or report was missed or late; it does not by itself mean a contaminant was found. "Health-based" marks violations of a legal limit or required treatment.
Mchenry: frequently asked questions
Who runs Mchenry?
Mchenry (PWSID IL1110600) is a community water system owned by a local government. It is regulated by the IL state drinking water program.
How many people does Mchenry serve?
Mchenry reports serving 22,335 people through 8,484 service connections in McHenry County, Illinois.
Where does Mchenry get its water?
EPA SDWIS lists this system's primary water source as groundwater. Groundwater means the system draws its water from wells or springs fed by underground aquifers.
Does Mchenry have any drinking water violations?
Of the 12 most recent violations in EPA's records, none is health-based, and the most recent began in July 2025. A monitoring or reporting violation means a required test or report was missed or late; it does not by itself mean a contaminant was found.
Is Mchenry's water safe to drink?
AquaCensus shows EPA compliance records, not current water test results, so it cannot say whether the water is safe at a given moment. Of the 12 most recent violations in EPA's records, none is health-based, and the most recent began in July 2025. For current results, consult the system's annual water quality report, EPA ECHO, or the IL state drinking water program.
Where can I find Mchenry's water quality report?
As a community water system, Mchenry must deliver an annual water quality report, called a Consumer Confidence Report, to its customers by July 1 each year, covering the previous calendar year. The system can provide a copy on request.
Other water systems in McHenry County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Crystal Lake | McHenry | 40,661 | Community | Groundwater |
| Algonquin | McHenry | 30,700 | Community | Groundwater |
| Lake in the Hills | McHenry | 28,661 | Community | Groundwater |
| Huntley | McHenry | 28,495 | Community | Groundwater |
| Woodstock | McHenry | 25,630 | Community | Groundwater |
| Cary | McHenry | 17,826 | Community | Groundwater |
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About this data
Source: U.S. EPA Safe Drinking Water Information System (SDWIS) and SDWA violation records, via EPA ECHO, as published October 1, 2026 — AquaCensus refreshes it quarterly. See the methodology for how records are matched, cleaned and scored.
Cite as: AquaCensus, “Mchenry, PWSID IL1110600, Illinois”, https://aquacensus.com/water-systems/illinois/mchenry-il1110600 (data as of October 1, 2026).