Public water system · IL1990200
ActiveColp
At a glance
Colp (PWSID IL1990200) is an active community water system in Williamson County, Illinois. It reports serving 506 people through 272 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, 2 are health-based, and the most recent began in July 2025.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
506
Service connections
272
Primary source
SWP
Purchased surface water
System type
CWS
Community water system
System record
How does Colp compare with other water systems in Williamson County?
By EPA's size categories, Colp is a small system (501 to 3,300 people). Williamson County has 25 active public water systems. Its population served is well below the county average of 3,018 people per system, and accounts for 0.7% 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 Colp 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 Colp?
EPA lists Colp 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 Colp have drinking water violations?
Of the 12 most recent violations in EPA's records, 2 are health-based, and the most recent began in July 2025. The violations listed here began between December 2004 and July 2025. By type: 5 public notice, recordkeeping or other, 4 monitoring and reporting, 2 required treatment not met and 1 reporting. The contaminant or rule involved most often is Consumer Confidence Rule (4 of them). EPA lists 10 as resolved 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. 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 |
|---|---|---|---|---|
| 2025-07-02 | ReportingNotification, Known or Potential LSL · code 4H | Lead and Copper Rule Revisionscode 5200 | No | Unaddressed |
| 2024-10-17 | Required treatment not metLSL Inventory · code 2E | Lead and Copper Rule Revisionscode 5200 | Yes | Unaddressed |
| 2024-07-11 | Public notice, recordkeeping or otherPublic Notification Violation for NPDWR Violation · code 75 | Public Noticecode 7500 | No | Resolved |
| 2024-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2023-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Inadequate Reporting · code 72 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2023-04-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Haloacetic acids (HAA5)code 2456 | No | Resolved |
| 2019-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Inadequate Reporting · code 72 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2014-11-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 2014-10-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Chloraminecode 1006 | No | Resolved |
| 2013-10-01 | Monitoring and reportingFollow-up Or Routine LCR Tap M/R · code 52 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2011-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Inadequate Reporting · code 72 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2004-12-14 | Required treatment not metPublic Education · code 65 | Lead and Copper Rulecode 5000 | Yes | 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.
Colp: frequently asked questions
Who runs Colp?
Colp (PWSID IL1990200) is a community water system owned by a local government. It is regulated by the IL state drinking water program.
How many people does Colp serve?
Colp reports serving 506 people through 272 service connections in Williamson County, Illinois.
Where does Colp 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 Colp have any drinking water violations?
Of the 12 most recent violations in EPA's records, 2 are health-based, and the most recent began in July 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 Colp'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, 2 are health-based, and the most recent began in July 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 Colp's water quality report?
As a community water system, Colp 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 |
Related pages
Working with water-system records? Pro adds alerts, change history and CSV export ($49/mo); Enterprise adds full national files, the API and an MCP server for AI tools.
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, “Colp, PWSID IL1990200, Illinois”, https://aquacensus.com/water-systems/illinois/colp-il1990200 (data as of October 1, 2026).