Is Illiopolis, IL Tap Water Safe to Drink?
Graded B-, with 8 unresolved violations on record. See what was cited — and what it means for your tap. What to do next ↓
72.8/100
waterverge.com Illiopolis, IL — Water Quality Report
Illiopolis's drinking water received a grade of B- (72.8 out of 100), indicating fair water quality. The city's 2 water systems serve approximately 1,062 residents using purchased ground water.
Lead levels were measured at 4.2 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 20 violations on record, including 5 health-based violations. 8 remain unresolved.
What to know about Illiopolis's water
Illiopolis ranks #705 out of 891 cities in Illinois for water quality, placing it among the lowest-rated in the state.
Illiopolis purchases its water from a regional wholesaler, meaning quality depends on both the supplier's treatment and the local distribution system's condition.
As a small community water system, Illiopolis may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
The system has seen 12 violations in the past five years, suggesting a pattern of compliance challenges that residents should monitor closely.
Water quality score
See methodology →Is Illiopolis, IL water safe to drink?
Illiopolis's drinking water has significant quality concerns based on EPA testing data. With a grade of B- (72.8/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 2 water systems serve approximately 1,062 residents using groundwater (wells).
Recent water quality updates for Illiopolis
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Illiopolis's water quality assessment. Grade: B- (72.8/100).
Contaminants: Lead and Copper Rule, TTHM, Total Haloacetic Acids (HAA5).
Contaminants: TTHM.
Contaminants: Lead and Copper Rule.
Federal disaster declaration (FEMA DR-3230). Hurricane event — may have impacted local water infrastructure.
Federal disaster declaration (FEMA DR-438). Flood event — may have impacted local water infrastructure.
Key contaminant findings
Based on the most recent EPA sampling data for Illiopolis's water supply.
Well within EPA limits.
Violation history
Illiopolis's water system has 20 total violations on record, including 5 health-based violations. 8 remain unresolved. 12 violations were issued in the last 5 years.
Flood & environmental risk
Sangamon County has experienced 2 federally declared disasters since 1974. Flooding and severe storms can overwhelm water treatment plants, cause sewage overflows, and introduce agricultural runoff, bacteria, and sediment into drinking water supplies. Local water sources include Lake Fork.
Where does Illiopolis's water come from?
Illiopolis's drinking water comes from groundwater (wells), supplied by 2 water systems serving approximately 1,062 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate. Nearby water bodies include Lake Fork (river).
What Illiopolis residents can do
Recommended: NSF-certified water filter. This addresses the specific contaminants found in Illiopolis's water.
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.
Run cold water for 30 seconds before drinking, especially in the morning. Lead and copper leach from household plumbing when water sits in pipes.
Data: EPA SDWIS, UCMR 5 (PFAS), FEMA, NOAA. Last updated May 2026.
Top contaminants to know
View all ↓Violation summary
Violations & advisories
Flood & disaster history
Sangamon County has experienced 2 federally declared disasters since 1974. Flooding and severe weather can compromise water treatment infrastructure and introduce contaminants into drinking water supplies.
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. | 4.2 | 15 | ppb | Inorganic | Safe |
Lead level trend (90th percentile)
See how Illiopolis compares by contaminant
Explore where Illiopolis ranks among all Illinois cities for specific contaminants.
Water source & infrastructure
Where Illiopolis's water comes from
Illiopolis 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 Illiopolis'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 1,062 people through 2 water systems.
Water bodies near Illiopolis
Illiopolis is located near 1 notable water body. These water bodies contribute to the regional watershed and may indirectly affect groundwater quality.
Water systems serving Illiopolis
| System Name | PWSID | Population | Source |
|---|---|---|---|
| ILLIOPOLIS | IL1670550 | 1,037 | GWP |
| UNITED REGIONAL WATER COOP | IL1670260 | 25 | GW |
How Illiopolis compares
Full Illinois rankings →Illiopolis's score of 72.8/100 is above the average of 56/100 among major Illinois cities. It outscores 7 of 10 nearby cities.
Nearby cities
View Illinois rankings →About Illiopolis, IL
Wikipedia →Illiopolis is a village in Sangamon County, Illinois, United States. As of the 2020 census, Illiopolis had a population of 846. It is part of the Springfield, Illinois Metropolitan Statistical Area.
Learn more about your water
Guides and resources related to Illiopolis's water quality findings.
Explore water quality across Sangamon
Frequently asked questions
Is Illiopolis, IL tap water safe to drink?
Illiopolis's water quality earned a grade of B- (72.8/100). Some concerns have been identified. Consider a water filter for an extra layer of protection. The city ranks #705 out of 891 cities tested in Illinois.
What contaminants are in Illiopolis's water?
Lead was measured at 4.2 ppb (90th percentile). 20 violations are on record.
How is Illiopolis'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 Illiopolis?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Illiopolis's water come from?
Illiopolis's water is sourced from Purchased ground water. The city has 2 water systems serving approximately 1,062 residents.
What health violations has Illiopolis's water system had?
Illiopolis has 5 health-based violations on record. The most recent violation was recorded in April 2025. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 8 violations remain unresolved.
Is Illiopolis's groundwater at risk of contamination?
Illiopolis 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 20 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 Illiopolis's water compare to other cities?
Illiopolis ranks #705 out of 891 cities in Illinois (better than 21% of state cities) and #10237 out of 15744 cities nationally (35th percentile). The grade of B- reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.