Public water system · IL1990500
ActiveJohnston City
At a glance
Johnston City (PWSID IL1990500) is an active community water system in Williamson County, Illinois. It reports serving 3,509 people through 1,913 service connections. Its primary water source is purchased surface water, and EPA lists it as owned by a local government. EPA's records list 10 violations for this system; 2 are health-based, and the most recent began in January 2026.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
3,509
Service connections
1,913
Primary source
SWP
Purchased surface water
System type
CWS
Community water system
System record
How does Johnston City compare with other water systems in Williamson County?
By EPA's size categories, Johnston City is a medium system (3,301 to 10,000 people). Williamson County has 25 active public water systems. Its population served is about 16% above the county average of 3,018 people per system, and accounts for 4.7% of the 75,458 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 Johnston City 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 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 Johnston City?
EPA lists Johnston City 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 25 active systems in Williamson County (80%) are also owned by a local government.
Does Johnston City have drinking water violations?
EPA's records list 10 violations for this system; 2 are health-based, and the most recent began in January 2026. The violations listed here began between June 1977 and January 2026. By type: 5 monitoring and reporting, 3 public notice, recordkeeping or other, 1 required treatment not met and 1 contaminant level above the legal limit. The contaminant or rule involved most often is Lead and Copper Rule (2 of them). EPA lists 5 as resolved, 3 as archived and 2 as unaddressed. 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. Unaddressed means the violation is not resolved or archived and is not yet covered by formal enforcement.
| Began | Violation | Contaminant or rule | Health-based | Status |
|---|---|---|---|---|
| 2026-01-01 | Monitoring and reportingFollow-up Or Routine LCR Tap M/R · code 52 | Lead and Copper Rulecode 5000 | No | Unaddressed |
| 2025-08-22 | Public notice, recordkeeping or otherPublic Notification Violation for NPDWR Violation · code 75 | Public Noticecode 7500 | No | Resolved |
| 2025-07-01 | Monitoring and reportingFollow-up Or Routine LCR Tap M/R · code 52 | Lead and Copper Rulecode 5000 | No | Unaddressed |
| 2024-10-17 | Required treatment not metLSL Inventory · code 2E | Lead and Copper Rule Revisionscode 5200 | Yes | Resolved |
| 2024-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Inadequate Reporting · code 72 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2018-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Inadequate Reporting · code 72 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2011-01-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Chloraminecode 1006 | No | Resolved |
| 1997-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Archived |
| 1992-02-01 | Monitoring and reportingMonitoring, Routine Minor (TCR) · code 24 | 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.
Johnston City: frequently asked questions
Who runs Johnston City?
Johnston City (PWSID IL1990500) is a community water system owned by a local government. It is regulated by the IL state drinking water program.
How many people does Johnston City serve?
Johnston City reports serving 3,509 people through 1,913 service connections in Williamson County, Illinois.
Where does Johnston City 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 Johnston City have any drinking water violations?
EPA's records list 10 violations for this system; 2 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 Johnston City'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; 2 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 Johnston City's water quality report?
As a community water system, Johnston City 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 Williamson County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Marion | Williamson | 16,855 | Community | Purchased surface water |
| Herrin | Williamson | 12,747 | Community | Purchased surface water |
| Lake of Egypt PWD | Williamson | 11,368 | Community | Surface water |
| Carterville | Williamson | 6,528 | Community | Purchased surface water |
| Coal Valley PWD | Williamson | 4,023 | Community | Purchased surface water |
| Corinth PWD | Williamson | 3,927 | 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, “Johnston City, PWSID IL1990500, Illinois”, https://aquacensus.com/water-systems/illinois/johnston-city-il1990500 (data as of October 1, 2026).