Public water system · IL0312790
ActiveSauk
At a glance
Sauk (PWSID IL0312790) is an active community water system in Cook County, Illinois. It reports serving 9,921 people through 3,200 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
9,921
Service connections
3,200
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Sauk compare with other water systems in Cook County?
By EPA's size categories, Sauk is a medium system (3,301 to 10,000 people). Cook County has 251 active public water systems. Its population served is about half of the county average of 20,993 people per system, and accounts for 0.2% 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 Sauk is about 48% above 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 Sauk?
EPA lists Sauk 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. 134 of the 251 active systems in Cook County (53%) are also owned by a local government.
Does Sauk 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 April 2024 and July 2025. By type: 6 public notice, recordkeeping or other and 6 monitoring and reporting. The contaminant or rule involved most often is Public Notice (4 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 |
|---|---|---|---|---|
| 2025-07-12 | Public notice, recordkeeping or otherPublic Notification Violation for NPDWR Violation · code 75 | Public Noticecode 7500 | No | Resolved |
| 2025-07-12 | Public notice, recordkeeping or otherPublic Notification Violation for NPDWR Violation · code 75 | Public Noticecode 7500 | No | Resolved |
| 2025-07-12 | Public notice, recordkeeping or otherPublic Notification Violation for NPDWR Violation · code 75 | Public Noticecode 7500 | No | Resolved |
| 2025-07-12 | Public notice, recordkeeping or otherPublic Notification Violation for NPDWR Violation · code 75 | Public Noticecode 7500 | No | Resolved |
| 2025-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2024-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Inadequate Reporting · code 72 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2024-04-01 | Monitoring and reportingMonitoring, Regular · code 03 | 1,1,1-Trichloroethanecode 2981 | No | Resolved |
| 2024-04-01 | Monitoring and reportingMonitoring, Regular · code 03 | Toluenecode 2991 | No | Resolved |
| 2024-04-01 | Monitoring and reportingMonitoring, Regular · code 03 | Benzenecode 2990 | No | Resolved |
| 2024-04-01 | Monitoring and reportingMonitoring, Regular · code 03 | Styrenecode 2996 | No | Resolved |
| 2024-04-01 | Monitoring and reportingMonitoring, Regular · code 03 | trans-1,2-Dichloroethylenecode 2979 | No | Resolved |
| 2024-04-01 | Monitoring and reportingMonitoring, Regular · code 03 | Ethylbenzenecode 2992 | 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.
Sauk: frequently asked questions
Who runs Sauk?
Sauk (PWSID IL0312790) is a community water system owned by a local government. It is regulated by the IL state drinking water program.
How many people does Sauk serve?
Sauk reports serving 9,921 people through 3,200 service connections in Cook County, Illinois.
Where does Sauk 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 Sauk 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 Sauk'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 Sauk's water quality report?
As a community water system, Sauk 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, “Sauk, PWSID IL0312790, Illinois”, https://aquacensus.com/water-systems/illinois/sauk-il0312790 (data as of October 1, 2026).