Is Colchester, IL Tap Water Safe to Drink?
Graded A- — but Copper was detected above EPA limits. Here's what's in the water and how to remove it. What to do next ↓
85/100
waterverge.com Colchester, IL — Water Quality Report
Colchester's drinking water received a grade of A- (85 out of 100), indicating good water quality. The city's 2 water systems serve approximately 3,790 residents using purchased ground water.
Lead levels were measured at 0.0 ppb (90th percentile), well within EPA limits. This system has not yet been tested for PFAS under the EPA UCMR 5 program.
The system has 33 violations on record, including 23 health-based violations. 2 remain unresolved.
What to know about Colchester's water
Colchester ranks #389 out of 891 cities in Illinois for water quality, placing it mid-range in the state.
Colchester purchases its water from a regional wholesaler, meaning quality depends on both the supplier's treatment and the local distribution system's condition.
Water quality score
See methodology →Is Colchester, IL water safe to drink?
Colchester's tap water meets most EPA standards but has areas that warrant attention. With a grade of A- (85/100), some contaminant levels or compliance issues suggest that residents may benefit from additional filtration. The city's 2 water systems serve approximately 3,790 residents using groundwater (wells).
Recent water quality updates for Colchester
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Colchester's water quality assessment. Grade: A- (85/100).
Contaminants: TTHM, Total Haloacetic Acids (HAA5).
Federal disaster declaration (FEMA DR-4116). Flood event — may have impacted local water infrastructure.
Contaminants: Coliform (TCR).
1 health-based. Contaminants: Interim Enhanced Surface Water Treatment Rule.
Federal disaster declaration (FEMA DR-3230). Hurricane event — may have impacted local water infrastructure.
Key contaminant findings
Based on the most recent EPA sampling data for Colchester's water supply.
Well within EPA limits.
Exceeds EPA action level. Copper can leach from household plumbing — flush taps for 30 seconds before drinking.
Violation history
Colchester's water system has 33 total violations on record, including 23 health-based violations. 2 remain unresolved. 2 violations were issued in the last 5 years.
Flood & environmental risk
McDonough County has experienced 2 federally declared disasters since 2005. Flooding and severe storms can overwhelm water treatment plants, cause sewage overflows, and introduce agricultural runoff, bacteria, and sediment into drinking water supplies.
Where does Colchester's water come from?
Colchester's drinking water comes from groundwater (wells), supplied by 2 water systems serving approximately 3,790 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate.
What Colchester residents can do
Your water utility is required to publish an annual Consumer Confidence Report (CCR) with detailed testing results. Ask for the latest copy or check your utility's website.
Data: EPA SDWIS, UCMR 5 (PFAS), FEMA, NOAA. Last updated May 2026.
Top contaminants to know
View all ↓Violation summary
Violations & advisories
Top industrial polluters within 10 miles of Colchester
Industrial polluters nearby
Reported releases to surface water by facilities near Colchester, ranked by pounds discharged annually.
| Facility | Top chemical | To surface water (lbs/yr) | Distance |
|---|---|---|---|
NTN-BOWER CORP MACOMB, IL61455 | — | — | 8.6 mi |
Source: EPA Toxic Release Inventory (TRI) 2023
Flood & disaster history
McDonough County has experienced 2 federally declared disasters since 2005. Flooding and severe weather can compromise water treatment infrastructure and introduce contaminants into drinking water supplies.
Recommended water filters
Based on contaminants detected in Colchester's water supply, we recommend the following filter types.
Full contaminants report
| Contaminant | Detected Level | EPA Limit | Unit | Category | Status |
|---|---|---|---|---|---|
| Lead (90th percentile) LeadHeavy Metal A toxic heavy metal that can leach into drinking water from older pipes, solder, and fixtures. No amount of lead in water is considered safe. Health EffectsBrain and nervous system damage in children, kidney damage, high blood pressure, and reproductive problems in adults. EPA Limit15 ppb action level Common SourcesCorrosion of lead pipes, lead solder, brass faucets, and household plumbing. | 0.0 | 15 | ppb | Inorganic | Safe |
| Copper (90th percentile) CopperInorganic A metal that enters drinking water mainly through corrosion of copper plumbing. Small amounts are essential for health, but excess levels are harmful. Health EffectsGastrointestinal distress (nausea, vomiting, diarrhea) at short-term high levels; liver and kidney damage from long-term exposure. EPA Limit1.3 mg/L action level Common SourcesCorrosion of copper household plumbing, erosion of natural deposits. | 2.33 | 1.3 | mg/L | Inorganic | Over Limit |
Lead level trend (90th percentile)
Copper level trend (90th percentile)
See how Colchester compares by contaminant
Explore where Colchester ranks among all Illinois cities for specific contaminants.
Water source & infrastructure
Where Colchester's water comes from
Colchester purchases its water supply from a regional wholesale provider rather than treating raw water directly.
Water quality depends on both the wholesaler's treatment standards and the condition of Colchester's local distribution pipes and storage facilities.
Purchased water systems are common in suburban areas and smaller communities that lack the infrastructure for independent treatment.
The system is operated by local government ownership and serves approximately 3,790 people through 2 water systems.
Water systems serving Colchester
| System Name | PWSID | Population | Source |
|---|---|---|---|
| WEST PRAIRIE WATER CO-OP | IL1090030 | 2,395 | GWP |
| COLCHESTER | IL1090200 | 1,395 | SWP |
How Colchester compares
Full Illinois rankings →Colchester's score of 85/100 is above the average of 56/100 among major Illinois cities. It outscores 9 of 10 nearby cities.
Nearby cities
View Illinois rankings →About Colchester, IL
Wikipedia →Macomb is a city in and the county seat of McDonough County, Illinois, United States. It is situated in western Illinois, about 75 miles (121 km) southwest of Peoria. As of the 2020 census, the population of the city was 15,051. Macomb is the home of Western Illinois University.
Learn more about your water
Guides and resources related to Colchester's water quality findings.
Explore water quality across Mcdonough
Frequently asked questions
Is Colchester, IL tap water safe to drink?
Colchester's water quality earned a grade of A- (85/100). The water generally meets EPA standards and is considered safe for consumption. The city ranks #389 out of 891 cities tested in Illinois.
What contaminants are in Colchester's water?
Lead was measured at 0.0 ppb (90th percentile). 33 violations are on record.
How is Colchester's water quality grade calculated?
The grade is based on four factors: violation history (40%), lead and copper levels (25%), PFAS contamination (25%), and regulatory compliance (10%). The score is also adjusted based on how complete the available data is. See our methodology page for full details.
Do I need a water filter in Colchester?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Colchester's water come from?
Colchester's water is sourced from Purchased ground water. The city has 2 water systems serving approximately 3,790 residents.
What health violations has Colchester's water system had?
Colchester has 23 health-based violations on record. The most recent violation was recorded in October 2021. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 2 violations remain unresolved.
Is Colchester's groundwater at risk of contamination?
Colchester uses groundwater, which can be affected by naturally occurring contaminants like arsenic, radon, and nitrate, as well as agricultural runoff and industrial activity. The system has 33 violations on record that may relate to groundwater quality. Groundwater systems are generally less susceptible to surface contamination but should be monitored for emerging contaminants like PFAS.
How does Colchester's water compare to other cities?
Colchester ranks #389 out of 891 cities in Illinois (better than 56% of state cities) and #5559 out of 15744 cities nationally (65th percentile). The grade of A- reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.