Public water system · IL0750700
ActiveOnarga
At a glance
Onarga (PWSID IL0750700) is an active community water system in Iroquois County, Illinois. It reports serving 1,409 people through 500 service connections. Its primary water source is groundwater, and EPA lists it as owned by a local government. EPA's records list 9 violations for this system; 1 is health-based, and the most recent began in October 2024.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
1,409
Service connections
500
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Onarga compare with other water systems in Iroquois County?
By EPA's size categories, Onarga is a small system (501 to 3,300 people). Iroquois County has 56 active public water systems, and Onarga is the 4th-largest of them by population served. Its population served is about 3.2 times the county average of 442 people per system, and accounts for 5.7% of the 24,775 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 Onarga 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 Onarga?
EPA lists Onarga 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. 19 of the 56 active systems in Iroquois County (34%) are also owned by a local government.
Does Onarga have drinking water violations?
EPA's records list 9 violations for this system; 1 is health-based, and the most recent began in October 2024. The violations listed here began between June 1977 and October 2024. By type: 4 monitoring and reporting, 3 public notice, recordkeeping or other, 1 monitoring and 1 required treatment not met. The contaminant or rule involved most often is Lead and Copper Rule (3 of them). EPA lists 8 as resolved and 1 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 |
|---|---|---|---|---|
| 2024-10-16 | Public notice, recordkeeping or otherPublic Notification Violation for NPDWR Violation · code 75 | Public Noticecode 7500 | No | Resolved |
| 2024-10-16 | Public notice, recordkeeping or otherPublic Notification Violation for NPDWR Violation · code 75 | Public Noticecode 7500 | No | Resolved |
| 2023-08-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2023-07-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Chlorinecode 0999 | No | Resolved |
| 2021-07-01 | Monitoring and reportingInitial, Follow-up, or Routine Source Water M/R · code 56 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2020-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2000-10-01 | Monitoring and reportingWater Quality Parameter M/R · code 53 | Lead and Copper Rulecode 5000 | No | Resolved |
| 1994-01-01 | Required treatment not metOCCT/SOWT Study/Recommendation · code 57 | Lead and Copper Rulecode 5000 | Yes | Resolved |
| 1977-06-30 | Monitoring and reportingMonitoring, Regular · code 03 | Gross alpha (excluding radon and uranium)code 4000 | No | Archived |
All 9 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.
Onarga: frequently asked questions
Who runs Onarga?
Onarga (PWSID IL0750700) is a community water system owned by a local government. It is regulated by the IL state drinking water program.
How many people does Onarga serve?
Onarga reports serving 1,409 people through 500 service connections in Iroquois County, Illinois.
Where does Onarga 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 Onarga have any drinking water violations?
EPA's records list 9 violations for this system; 1 is health-based, and the most recent began in October 2024. 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 Onarga'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 9 violations for this system; 1 is health-based, and the most recent began in October 2024. For current results, consult the system's annual water quality report, EPA ECHO, or the IL state drinking water program.
Where can I find Onarga's water quality report?
As a community water system, Onarga 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 Iroquois County
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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, “Onarga, PWSID IL0750700, Illinois”, https://aquacensus.com/water-systems/illinois/onarga-il0750700 (data as of October 1, 2026).