Public water system · IL3163725
ActiveNorthwestern Medicine Woodstock Hospital
At a glance
Northwestern Medicine Woodstock Hospital (PWSID IL3163725) is an active non-transient non-community water system in McHenry County, Illinois. It reports serving 300 people through 1 service connection. Its primary water source is purchased groundwater, and EPA lists it as privately owned. EPA's records list 9 violations for this system; 1 is health-based, and the most recent began in December 2025.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
300
Service connections
1
Primary source
GWP
Purchased groundwater
System type
NTNCWS
Non-transient non-community water system
System record
How does Northwestern Medicine Woodstock Hospital compare with other water systems in McHenry County?
By EPA's size categories, Northwestern Medicine Woodstock Hospital is a very small system (500 people or fewer). McHenry County has 192 active public water systems. Its population served is well below the county average of 1,331 people per system, and accounts for 0.1% 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 non-transient non-community water system reports serving 430 people, so Northwestern Medicine Woodstock Hospital is about 30% below that figure.
What does “non-transient non-community water system” mean?
A non-transient non-community water system regularly serves at least 25 of the same people for more than six months a year, but not where they live. Schools, factories, office buildings and hospitals with their own supply are typical examples. Illinois has 396 active non-transient non-community water systems, 10% of the state's 3,872 active systems. Purchased groundwater means the system buys groundwater from another public water system rather than drawing its own. 348 Illinois systems (9%) list purchased groundwater as their primary source.
Who owns and regulates Northwestern Medicine Woodstock Hospital?
EPA lists Northwestern Medicine Woodstock Hospital as privately owned. 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. 154 of the 192 active systems in McHenry County (80%) are also privately owned.
Does Northwestern Medicine Woodstock Hospital have drinking water violations?
EPA's records list 9 violations for this system; 1 is health-based, and the most recent began in December 2025. The violations listed here began between January 2022 and December 2025. By type: 8 monitoring and reporting and 1 required treatment not met. The contaminant or rule involved most often is Haloacetic acids (HAA5) (3 of them). EPA lists 8 as resolved and 1 as unaddressed. 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. Unaddressed means the violation is not resolved or archived and is not yet covered by formal enforcement.
| Began | Violation | Contaminant or rule | Health-based | Status |
|---|---|---|---|---|
| 2025-12-28 | Monitoring and reportingLead Consumer Notice · code 66 | Lead and Copper Rulecode 5000 | No | Unaddressed |
| 2025-04-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Haloacetic acids (HAA5)code 2456 | No | Resolved |
| 2025-04-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Total trihalomethanes (TTHM)code 2950 | No | Resolved |
| 2025-01-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Haloacetic acids (HAA5)code 2456 | No | Resolved |
| 2025-01-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Total trihalomethanes (TTHM)code 2950 | No | Resolved |
| 2023-04-09 | Monitoring and reportingLead Consumer Notice · code 66 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2022-01-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Total trihalomethanes (TTHM)code 2950 | No | Resolved |
| 2022-01-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Haloacetic acids (HAA5)code 2456 | No | Resolved |
| 2022-01-01 | Required treatment not metTreatment Technique No Certif. Operator · code 12 | Stage 1 Disinfectants and Disinfection Byproducts Rulecode 0400 | Yes | Resolved |
All 9 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.
Northwestern Medicine Woodstock Hospital: frequently asked questions
Who runs Northwestern Medicine Woodstock Hospital?
Northwestern Medicine Woodstock Hospital (PWSID IL3163725) is a non-transient non-community water system privately owned. It is regulated by the IL state drinking water program.
How many people does Northwestern Medicine Woodstock Hospital serve?
Northwestern Medicine Woodstock Hospital reports serving 300 people through 1 service connection in McHenry County, Illinois.
Where does Northwestern Medicine Woodstock Hospital get its water?
EPA SDWIS lists this system's primary water source as purchased groundwater. Purchased groundwater means the system buys groundwater from another public water system rather than drawing its own.
Does Northwestern Medicine Woodstock Hospital have any drinking water violations?
EPA's records list 9 violations for this system; 1 is health-based, and the most recent began in December 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 Northwestern Medicine Woodstock Hospital'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. EPA's records list 9 violations for this system; 1 is health-based, and the most recent began in December 2025. For current results, consult EPA ECHO, or the IL state drinking water program.
Where can I find Northwestern Medicine Woodstock Hospital's water quality report?
The annual Consumer Confidence Report requirement applies to community water systems. Northwestern Medicine Woodstock Hospital is a non-transient non-community water system, so it is not required to publish one; like every public water system, it must notify the people it serves about violations under EPA's public notification rules.
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 |
| Mchenry | McHenry | 22,335 | 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, “Northwestern Medicine Woodstock Hospital, PWSID IL3163725, Illinois”, https://aquacensus.com/water-systems/illinois/northwestern-medicine-woodstock-hospital-il3163725 (data as of October 1, 2026).