Colp
EPA ID: IL1990200 · 506 people served · 3 ZIP codes
Five-year compliance data for Colp includes 2 violations the EPA has not yet marked resolved — those open findings are part of the utility's current enforcement profile, covering a service population of approximately 506 residents across the area it supplies.
Data: EPA SDWIS Last verified: 2026-04-02
Compliance Trajectory
Worsening · Risk tier: High · 95% chance of violation in next 12 months
Violations went from 17 (2024) to 6 (2025). The pattern suggests growing compliance challenges.
Service Area Map
Coverage area for Colp Source: EPA SDWIS service area boundaries.
Service area boundary — Grade C
Service Area Demographics
The Colp serves a community with a median household income of $57,721 and an estimated 13,785 residents across its service area. Approximately 58% of housing stock was built before 1986, which increases the likelihood of lead service lines and older plumbing.
Environmental Justice Note: 36% of the population in this service area is classified as disadvantaged under EPA's EJScreen criteria. Communities with higher disadvantaged populations often face disproportionate environmental and health burdens, including aging water infrastructure and limited resources for remediation.
🌊 Where Does Your Water Come From?
Colp's water is drawn from rivers, lakes, or reservoirs. Surface water sources are more exposed to agricultural runoff, stormwater, and upstream discharges, but they typically receive more intensive treatment before reaching your tap.
About 1% of homes in Williamson County, Illinois rely on private wells rather than public water systems. Private well owners are responsible for their own water testing and treatment.
Wastewater Proximity Note: This service area ranks in the 67th percentile nationally for proximity to wastewater discharge points. Surface water sources near wastewater outfalls may face additional treatment challenges.
Infrastructure Risk
Detected Contaminants
How Colp compares to EPA limits
What This Means For You
Total Trihalomethanes (TTHM) at 1 mg/L exceeds the EPA maximum of 0.08 mg/L. Bladder & rectal cancer risk; reproductive concerns. Consider granular activated carbon (GAC) filtration.
Stage 2 DBP Rule at 2 mg/L exceeds the EPA maximum of mg/L.
Surface Water Treatment Rule at 2 mg/L exceeds the EPA maximum of mg/L.
Lead and Copper Rule at 1 mg/L exceeds the EPA maximum of mg/L.
PFAS Detected in Service Area
PFAS ("forever chemicals") have been detected in water serving this system's area. 1 detection recorded.
Total Trihalomethanes (TTHM) was detected in this water system. granular activated carbon (GAC) filtration can reduce exposure.
Find a certified water filter →Comparable Water Systems
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Estimated Remediation Costs
Average estimated costs across ZIP codes served by this system
Based on national averages for common remediation projects. Actual costs vary by property. Only issues flagged by EPA, FEMA, or state data for each ZIP code are included.
System Overview
Colp (EPA ID: IL1990200) is a community water system in Illinois that serves approximately 506 people from surface water sources.
This system provides water to 3 ZIP codes across 3 communities.
Average Home Safety Score: C (67/100)
Based on water quality violations, lead levels, and radon risk across all ZIP codes served by this system.
Violation History
Recent Violations
| Date | Contaminant | Type | Status |
|---|---|---|---|
| July 2, 2025 | Stage 2 DBP Rule | Monitoring | Unresolved |
| October 17, 2024 | Stage 2 DBP Rule | Health-based | Unresolved |
| July 11, 2024 | Lead and Copper Rule | Monitoring | Resolved |
| July 1, 2024 | Surface Water Treatment Rule | Monitoring | Resolved |
| July 1, 2023 | Surface Water Treatment Rule | Monitoring | Resolved |
| April 1, 2023 | Total Trihalomethanes (TTHM) | Monitoring | Resolved |
Contaminants Detected
The following contaminants have been flagged in EPA records for this water system:
| Contaminant | Category | Violations | Health-Based |
|---|---|---|---|
| Stage 2 DBP Rule | Treatment Failure | 2 | Yes |
| Surface Water Treatment Rule | Treatment Failure | 2 | No |
| Total Trihalomethanes (TTHM) | Disinfection Byproducts | 1 | No |
| Lead and Copper Rule | Treatment Failure | 1 | No |
Lead & Copper
No Lead and Copper Rule sampling data available for this water system.
Radon Risk in Service Area
Dominant radon zone for ZIP codes served by this system: Zone 2 (Moderate Risk)
The EPA recommends testing homes in Zone 1 and Zone 2 areas for radon.
Need help with your water quality?
Typical cost: Water test: typically $20–$50 (DIY kit) · Professional inspection: $150–$400
Find the Right Water FilterFree tip: Let cold water run for 2 minutes before drinking — this helps flush lead from your pipes.
ZIP Codes Served
Coverage: 2 ZIP codes confirmed via EPA Community Water System Service Area Boundaries v3 plus 1 additional ZIP inferred from SDWIS registry data. The EPA-confirmed set is the most reliable; SDWIS-inferred entries may be narrower than the real deployment area.
Data Sources
This report uses public data from the EPA Safe Drinking Water Information System (SDWIS). View the full compliance record for Colp (IL1990200) on EPA.gov.
Frequently Asked Questions
Is Colp water safe to drink?
Colp has recorded 1 health-based violation in the past 5 years. While the system is required to treat water to meet federal standards, you may want to consider additional precautions such as a certified water filter.
How many people does Colp serve?
Colp serves approximately 506 people across 3 ZIP codes in Illinois.
Where does Colp get its water?
The primary water source is surface water.
Treatment regime
How this utility classifies its treatment process and what each reported treatment chemical does.
Treatment chemicals and what each one does
Chemical names are reported verbatim by the utility. Purpose categories are ZipCheckup annotations based on standard drinking-water treatment practice.
Treatment classification and chemical list sourced from COLP Consumer Confidence Report.
Treatment intensity is a ZipCheckup-derived classification based on the chemicals and processes the utility reports. Chemicals and contamination sources are taken verbatim from the utility's CCR filing. Routine federal monitoring and contaminant testing shown elsewhere on this page determine whether the water meets safety standards, not the treatment classification.
Frequently Asked Questions
What You Can Do
Test your water
Home test kits can detect lead, bacteria, and other contaminants at your tap. Find the right filter →
Check your specific ZIP code
Water quality can vary within a system. View nearest ZIP report →
Contact your utility
Colp (EPA ID: IL1990200) — request the latest Consumer Confidence Report or ask about specific contaminants.