Public water system · IL1110150
ActiveCrystal Lake
At a glance
Crystal Lake (PWSID IL1110150) is an active community water system in McHenry County, Illinois. It reports serving 40,661 people through 14,101 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 January 2026.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
40,661
Service connections
14,101
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Crystal Lake compare with other water systems in McHenry County?
By EPA's size categories, Crystal Lake is a large system (10,001 to 100,000 people). McHenry County has 192 active public water systems, and Crystal Lake is the largest of them by population served. Its population served is about 31 times the county average of 1,331 people per system, and accounts for 16% 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 Crystal Lake is about 6.1 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 Crystal Lake?
EPA lists Crystal Lake 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 Crystal Lake have drinking water violations?
Of the 12 most recent violations in EPA's records, none is health-based, and the most recent began in January 2026. The violations listed here began between January 2026 and January 2026. By type: 12 monitoring and reporting. The contaminants or rules involved are Heptachlor epoxide, Endrin, Alachlor (Lasso) and Hexachlorocyclopentadiene. EPA lists 12 as archived. Archived means the violation was not marked resolved but is more than five years past the end of the noncompliance period, so it no longer counts toward current compliance status.
| Began | Violation | Contaminant or rule | Health-based | Status |
|---|---|---|---|---|
| 2026-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Heptachlor epoxidecode 2067 | No | Archived |
| 2026-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Endrincode 2005 | No | Archived |
| 2026-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Alachlor (Lasso)code 2051 | No | Archived |
| 2026-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Hexachlorocyclopentadienecode 2042 | No | Archived |
| 2026-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Atrazinecode 2050 | No | Archived |
| 2026-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Di(2-ethylhexyl) adipatecode 2035 | No | Archived |
| 2026-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Di(2-ethylhexyl) phthalatecode 2039 | No | Archived |
| 2026-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Simazinecode 2037 | No | Archived |
| 2026-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Lindane (gamma-BHC)code 2010 | No | Archived |
| 2026-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Methoxychlorcode 2015 | No | Archived |
| 2026-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Heptachlorcode 2065 | No | Archived |
| 2026-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Hexachlorobenzenecode 2274 | No | Archived |
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.
Crystal Lake: frequently asked questions
Who runs Crystal Lake?
Crystal Lake (PWSID IL1110150) is a community water system owned by a local government. It is regulated by the IL state drinking water program.
How many people does Crystal Lake serve?
Crystal Lake reports serving 40,661 people through 14,101 service connections in McHenry County, Illinois.
Where does Crystal Lake 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 Crystal Lake 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 January 2026. 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 Crystal Lake'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 January 2026. For current results, consult the system's annual water quality report, EPA ECHO, or the IL state drinking water program.
Where can I find Crystal Lake's water quality report?
As a community water system, Crystal Lake 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
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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, “Crystal Lake, PWSID IL1110150, Illinois”, https://aquacensus.com/water-systems/illinois/crystal-lake-il1110150 (data as of October 1, 2026).