Public water system · IL1170250
ActiveDorchester
At a glance
Dorchester (PWSID IL1170250) is an active community water system in Macoupin County, Illinois. It reports serving 540 people through 219 service connections. Its primary water source is purchased surface water, and EPA lists it as owned by a local government. Of the 12 most recent violations in EPA's records, 4 are health-based, and the most recent began in January 2026.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
540
Service connections
219
Primary source
SWP
Purchased surface water
System type
CWS
Community water system
System record
How does Dorchester compare with other water systems in Macoupin County?
By EPA's size categories, Dorchester is a small system (501 to 3,300 people). Macoupin County has 32 active public water systems. Its population served is about 62% below the county average of 1,411 people per system, and accounts for 1.2% of the 45,161 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 Dorchester 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. Purchased surface water means the system buys surface water from another public water system rather than drawing its own. 619 Illinois systems (16%) list purchased surface water as their primary source.
Who owns and regulates Dorchester?
EPA lists Dorchester 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. 28 of the 32 active systems in Macoupin County (88%) are also owned by a local government.
Does Dorchester have drinking water violations?
Of the 12 most recent violations in EPA's records, 4 are health-based, and the most recent began in January 2026. The violations listed here began between November 1996 and January 2026. By type: 6 monitoring and reporting, 3 contaminant level above the legal limit, 2 public notice, recordkeeping or other and 1 required treatment not met. The contaminant or rule involved most often is Atrazine (3 of them). EPA lists 9 as resolved and 3 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 |
|---|---|---|---|---|
| 2026-01-01 | Required treatment not metTreatment Technique (SWTR and GWR) · code 41 | Long Term 2 Enhanced Surface Water Treatment Rulecode 0800 | Yes | Archived |
| 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 |
| 2011-01-02 | Monitoring and reportingLead Consumer Notice · code 66 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2010-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Inadequate Reporting · code 72 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2005-10-01 | Monitoring and reportingFollow-up Or Routine LCR Tap M/R · code 52 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2004-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Inadequate Reporting · code 72 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 1997-07-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Archived |
| 1997-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Atrazinecode 2050 | Yes | Resolved |
| 1997-04-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Atrazinecode 2050 | Yes | Resolved |
| 1997-01-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Atrazinecode 2050 | Yes | Resolved |
| 1996-11-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | 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.
Dorchester: frequently asked questions
Who runs Dorchester?
Dorchester (PWSID IL1170250) is a community water system owned by a local government. It is regulated by the IL state drinking water program.
How many people does Dorchester serve?
Dorchester reports serving 540 people through 219 service connections in Macoupin County, Illinois.
Where does Dorchester get its water?
EPA SDWIS lists this system's primary water source as purchased surface water. Purchased surface water means the system buys surface water from another public water system rather than drawing its own.
Does Dorchester have any drinking water violations?
Of the 12 most recent violations in EPA's records, 4 are 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 Dorchester'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, 4 are 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 Dorchester's water quality report?
As a community water system, Dorchester 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 Macoupin County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Carlinville | Macoupin | 6,598 | Community | Surface water |
| Staunton | Macoupin | 5,756 | Community | Surface water |
| Brighton | Macoupin | 5,041 | Community | Purchased surface water |
| Gillespie | Macoupin | 3,737 | Community | Surface water |
| Virden | Macoupin | 3,274 | Community | Purchased surface water |
| Mount Olive | Macoupin | 2,193 | 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, “Dorchester, PWSID IL1170250, Illinois”, https://aquacensus.com/water-systems/illinois/dorchester-il1170250 (data as of October 1, 2026).