Public water system · IL0950450
ActiveRio
At a glance
Rio (PWSID IL0950450) is an active community water system in Knox County, Illinois. It reports serving 265 people through 106 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 November 2008.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
265
Service connections
106
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Rio compare with other water systems in Knox County?
By EPA's size categories, Rio is a very small system (500 people or fewer). Knox County has 34 active public water systems. Its population served is well below the county average of 1,442 people per system, and accounts for 0.5% of the 49,041 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 Rio 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 Rio?
EPA lists Rio 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. 14 of the 34 active systems in Knox County (41%) are also owned by a local government.
Does Rio have drinking water violations?
Of the 12 most recent violations in EPA's records, none is health-based, and the most recent began in November 2008. The violations listed here began between April 1994 and November 2008. By type: 12 monitoring and reporting. The contaminant or rule involved most often is Total coliform bacteria (TCR) (3 of them). EPA lists 10 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 |
|---|---|---|---|---|
| 2008-11-01 | Monitoring and reportingMonitoring, Repeat Major (TCR) · code 25 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 1995-10-01 | Monitoring and reportingFollow-up Or Routine LCR Tap M/R · code 52 | Lead and Copper Rulecode 5000 | No | Resolved |
| 1995-09-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Archived |
| 1994-07-01 | Monitoring and reportingInitial Tap Sampling for Pb and Cu · code 51 | Lead and Copper Rulecode 5000 | No | Resolved |
| 1994-06-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Archived |
| 1994-04-01 | Monitoring and reportingMonitoring, Regular · code 03 | Dichloromethanecode 2964 | No | Resolved |
| 1994-04-01 | Monitoring and reportingMonitoring, Regular · code 03 | trans-1,2-Dichloroethylenecode 2979 | No | Resolved |
| 1994-04-01 | Monitoring and reportingMonitoring, Regular · code 03 | Chlorobenzenecode 2989 | No | Resolved |
| 1994-04-01 | Monitoring and reportingMonitoring, Regular · code 03 | 1,2-Dichloropropanecode 2983 | No | Resolved |
| 1994-04-01 | Monitoring and reportingMonitoring, Regular · code 03 | o-Dichlorobenzenecode 2968 | No | Resolved |
| 1994-04-01 | Monitoring and reportingMonitoring, Regular · code 03 | Tetrachloroethylenecode 2987 | No | Resolved |
| 1994-04-01 | Monitoring and reportingMonitoring, Regular · code 03 | Toluenecode 2991 | 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.
Rio: frequently asked questions
Who runs Rio?
Rio (PWSID IL0950450) is a community water system owned by a local government. It is regulated by the IL state drinking water program.
How many people does Rio serve?
Rio reports serving 265 people through 106 service connections in Knox County, Illinois.
Where does Rio 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 Rio 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 November 2008. 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 Rio'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 November 2008. For current results, consult the system's annual water quality report, EPA ECHO, or the IL state drinking water program.
Where can I find Rio's water quality report?
As a community water system, Rio 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 Knox County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Galesburg | Knox | 31,620 | Community | Groundwater |
| Abingdon | Knox | 3,275 | Community | Purchased groundwater |
| Knoxville | Knox | 3,120 | Community | Purchased groundwater |
| I74 Spoon River Rest Area | Knox | 2,356 | Transient non-community | Groundwater |
| Aqua Illinois-Oak Run | Knox | 1,885 | Community | Groundwater |
| Wataga | Knox | 965 | 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, “Rio, PWSID IL0950450, Illinois”, https://aquacensus.com/water-systems/illinois/rio-il0950450 (data as of October 1, 2026).