Public water system · IL1670550
ActiveIlliopolis
At a glance
Illiopolis (PWSID IL1670550) is an active community water system in Sangamon County, Illinois. It reports serving 1,037 people through 445 service connections. Its primary water source is purchased groundwater, 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 April 2025.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
1,037
Service connections
445
Primary source
GWP
Purchased groundwater
System type
CWS
Community water system
System record
How does Illiopolis compare with other water systems in Sangamon County?
By EPA's size categories, Illiopolis is a small system (501 to 3,300 people). Sangamon County has 43 active public water systems. Its population served is well below the county average of 4,245 people per system, and accounts for 0.6% of the 182,536 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 Illiopolis 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 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 Illiopolis?
EPA lists Illiopolis 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. 20 of the 43 active systems in Sangamon County (47%) are also owned by a local government.
Does Illiopolis have drinking water violations?
Of the 12 most recent violations in EPA's records, 4 are health-based, and the most recent began in April 2025. The violations listed here began between October 2006 and April 2025. By type: 6 monitoring and reporting, 4 contaminant level above the legal limit and 2 public notice, recordkeeping or other. The contaminant or rule involved most often is Total trihalomethanes (TTHM) (6 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 |
|---|---|---|---|---|
| 2025-04-01 | 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 |
| 2024-07-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Total trihalomethanes (TTHM)code 2950 | No | Resolved |
| 2023-10-01 | Monitoring and reportingFollow-up Or Routine LCR Tap M/R · code 52 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2023-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Inadequate Reporting · code 72 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2022-04-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Total trihalomethanes (TTHM)code 2950 | Yes | Resolved |
| 2022-01-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Total trihalomethanes (TTHM)code 2950 | Yes | Resolved |
| 2021-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Total trihalomethanes (TTHM)code 2950 | Yes | Resolved |
| 2021-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Total trihalomethanes (TTHM)code 2950 | Yes | Resolved |
| 2020-01-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Chlorinecode 0999 | No | Resolved |
| 2017-01-01 | Monitoring and reportingLead Consumer Notice · code 66 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2006-10-14 | Public notice, recordkeeping or otherPublic Notification Violation for NPDWR Violation · code 75 | Public Noticecode 7500 | 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.
Illiopolis: frequently asked questions
Who runs Illiopolis?
Illiopolis (PWSID IL1670550) is a community water system owned by a local government. It is regulated by the IL state drinking water program.
How many people does Illiopolis serve?
Illiopolis reports serving 1,037 people through 445 service connections in Sangamon County, Illinois.
Where does Illiopolis 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 Illiopolis 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 April 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 Illiopolis' 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 April 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 Illiopolis' water quality report?
As a community water system, Illiopolis 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 Sangamon County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Springfield | Sangamon | 117,444 | Community | Surface water |
| Chatham | Sangamon | 16,423 | Community | Purchased groundwater |
| Curran-Gardner Township PWD | Sangamon | 6,651 | Community | Groundwater |
| Williamsville | Sangamon | 6,198 | Community | Purchased surface water |
| Auburn | Sangamon | 4,574 | Community | Purchased surface water |
| Riverton | Sangamon | 4,279 | 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, “Illiopolis, PWSID IL1670550, Illinois”, https://aquacensus.com/water-systems/illinois/illiopolis-il1670550 (data as of October 1, 2026).