Public water system · IL0090100
ActiveMount Sterling
At a glance
Mount Sterling (PWSID IL0090100) is an active community water system in Brown County, Illinois. It reports serving 3,271 people through 1,258 service connections. Its primary water source is purchased groundwater, and EPA lists it as owned by a local government. EPA's records list 10 violations for this system; 1 is health-based, and the most recent began in October 2025.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
3,271
Service connections
1,258
Primary source
GWP
Purchased groundwater
System type
CWS
Community water system
System record
How does Mount Sterling compare with other water systems in Brown County?
By EPA's size categories, Mount Sterling is a small system (501 to 3,300 people). Brown County has 5 active public water systems, and Mount Sterling is the largest of them by population served. Its population served is about 186% above the county average of 1,144 people per system, and accounts for 57% of the 5,721 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 Mount Sterling is about half of 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. 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 Mount Sterling?
EPA lists Mount Sterling 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. 4 of the 5 active systems in Brown County (80%) are also owned by a local government.
Does Mount Sterling have drinking water violations?
EPA's records list 10 violations for this system; 1 is health-based, and the most recent began in October 2025. The violations listed here began between June 1977 and October 2025. By type: 5 monitoring and reporting, 3 public notice, recordkeeping or other, 1 monitoring and 1 contaminant level above the legal limit. The contaminant or rule involved most often is Consumer Confidence Rule (3 of them). EPA lists 8 as resolved and 2 as archived. 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. 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 |
|---|---|---|---|---|
| 2025-10-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Chlorinecode 0999 | No | Resolved |
| 2025-10-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2013-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Inadequate Reporting · code 72 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2010-01-02 | Monitoring and reportingLead Consumer Notice · code 66 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2009-10-30 | Public notice, recordkeeping or otherConsumer Confidence Report Inadequate Reporting · code 72 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2007-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2005-06-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2005-06-01 | Monitoring and reportingMonitoring, Repeat Major (TCR) · code 25 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 1996-01-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Archived |
| 1977-06-30 | Monitoring and reportingMonitoring, Regular · code 03 | Gross alpha (excluding radon and uranium)code 4000 | No | Archived |
All 10 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.
Mount Sterling: frequently asked questions
Who runs Mount Sterling?
Mount Sterling (PWSID IL0090100) is a community water system owned by a local government. It is regulated by the IL state drinking water program.
How many people does Mount Sterling serve?
Mount Sterling reports serving 3,271 people through 1,258 service connections in Brown County, Illinois.
Where does Mount Sterling 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 Mount Sterling have any drinking water violations?
EPA's records list 10 violations for this system; 1 is health-based, and the most recent began in October 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 Mount Sterling'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 10 violations for this system; 1 is health-based, and the most recent began in October 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 Mount Sterling's water quality report?
As a community water system, Mount Sterling 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 Brown County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Western Il Correctional Center | Brown | 1,600 | Community | Purchased groundwater |
| Versailles | Brown | 478 | Community | Groundwater |
| Ripley | Brown | 250 | Community | Purchased groundwater |
| Mound Station | Brown | 122 | Community | Purchased 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, “Mount Sterling, PWSID IL0090100, Illinois”, https://aquacensus.com/water-systems/illinois/mount-sterling-il0090100 (data as of October 1, 2026).