Public water system · IL0317595
ActiveWilloway Terrace MHP
At a glance
Willoway Terrace MHP (PWSID IL0317595) is an active community water system in Cook County, Illinois. It reports serving 900 people through 320 service connections. Its primary water source is groundwater, and EPA lists it as privately owned. EPA's records list 6 violations for this system; 2 are health-based, and the most recent began in February 2023.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
900
Service connections
320
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Willoway Terrace MHP compare with other water systems in Cook County?
By EPA's size categories, Willoway Terrace MHP is a small system (501 to 3,300 people). Cook County has 251 active public water systems. Its population served is well below the county average of 20,993 people per system, and accounts for less than 0.1% of the 5,269,212 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 Willoway Terrace MHP is well below 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 Willoway Terrace MHP?
EPA lists Willoway Terrace MHP 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. 108 of the 251 active systems in Cook County (43%) are also privately owned.
Does Willoway Terrace MHP have drinking water violations?
EPA's records list 6 violations for this system; 2 are health-based, and the most recent began in February 2023. The violations listed here began between November 1992 and February 2023. By type: 3 monitoring and reporting, 2 contaminant level above the legal limit and 1 monitoring. The contaminant or rule involved most often is Total coliform bacteria (TCR) (4 of them). EPA lists 4 as archived and 2 as resolved. 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. 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 |
|---|---|---|---|---|
| 2023-02-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2023-01-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Chlorinecode 0999 | No | Resolved |
| 1992-12-01 | Monitoring and reportingMonitoring, Routine Minor (TCR) · code 24 | Total coliform bacteria (TCR)code 3100 | No | Archived |
| 1992-11-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Acute (TCR) · code 21 | Total coliform bacteria (TCR)code 3100 | Yes | Archived |
| 1992-11-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Archived |
| 1992-11-01 | Monitoring and reportingMonitoring, Repeat Major (TCR) · code 25 | Total coliform bacteria (TCR)code 3100 | No | Archived |
All 6 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.
Willoway Terrace MHP: frequently asked questions
Who runs Willoway Terrace MHP?
Willoway Terrace MHP (PWSID IL0317595) is a community water system privately owned. It is regulated by the IL state drinking water program.
How many people does Willoway Terrace MHP serve?
Willoway Terrace MHP reports serving 900 people through 320 service connections in Cook County, Illinois.
Where does Willoway Terrace MHP 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 Willoway Terrace MHP have any drinking water violations?
EPA's records list 6 violations for this system; 2 are health-based, and the most recent began in February 2023. 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 Willoway Terrace MHP'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 6 violations for this system; 2 are health-based, and the most recent began in February 2023. For current results, consult the system's annual water quality report, EPA ECHO, or the IL state drinking water program.
Where can I find Willoway Terrace MHP's water quality report?
As a community water system, Willoway Terrace MHP 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 Cook County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Chicago | Cook | 2,721,308 | Community | Surface water |
| Cicero | Cook | 83,000 | Community | Purchased surface water |
| Schaumburg | Cook | 75,750 | Community | Purchased surface water |
| Evanston | Cook | 74,486 | Community | Surface water |
| Arlington Heights | Cook | 73,320 | Community | Purchased surface water |
| Palatine | Cook | 70,875 | Community | Purchased surface water |
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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, “Willoway Terrace MHP, PWSID IL0317595, Illinois”, https://aquacensus.com/water-systems/illinois/willoway-terrace-mhp-il0317595 (data as of October 1, 2026).