Is Assumption, IL Tap Water Safe to Drink?
Graded C+, with 9 unresolved violations on record. See what was cited — and what it means for your tap. What to do next ↓
65/100
waterverge.com Assumption, IL — Water Quality Report
Assumption's drinking water received a grade of C+ (65 out of 100), indicating fair water quality. The city's 1 water system serves approximately 1,315 residents using groundwater.
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 19 violations on record, including 4 health-based violations. 9 remain unresolved.
What to know about Assumption's water
Assumption ranks #781 out of 891 cities in Illinois for water quality, placing it among the lowest-rated in the state.
Assumption relies on groundwater, which is generally less vulnerable to surface contamination but can be affected by naturally occurring minerals like arsenic and nitrate, as well as agricultural and industrial runoff.
As a small community water system, Assumption may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
The system has seen 15 violations in the past five years, suggesting a pattern of compliance challenges that residents should monitor closely.
Water quality score
See methodology →Is Assumption, IL water safe to drink?
Assumption's drinking water has significant quality concerns based on EPA testing data. With a grade of C+ (65/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 1 water system serves approximately 1,315 residents using groundwater (wells).
Recent water quality updates for Assumption
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Assumption's water quality assessment. Grade: C+ (65/100).
Contaminants: Public Notice.
Contaminants: Public Notice.
2 health-based. Contaminants: LEAD AND COPPER RULE REVISIONS, TTHM.
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 Assumption's water supply.
Well within EPA limits.
Violation history
Assumption's water system has 19 total violations on record, including 4 health-based violations. 9 remain unresolved. 15 violations were issued in the last 5 years.
Flood & environmental risk
Christian County has experienced 1 federally declared disaster 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 Assumption's water come from?
Assumption's drinking water comes from groundwater (wells), supplied by 1 water system serving approximately 1,315 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate.
What Assumption residents can do
Recommended: NSF-certified water filter. This addresses the specific contaminants found in Assumption'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.
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 Assumption
Industrial polluters nearby
Reported releases to surface water by facilities near Assumption, ranked by pounds discharged annually.
| Facility | Top chemical | To surface water (lbs/yr) | Distance |
|---|---|---|---|
GSI GROUP LLC ASSUMPTION, IL62510 | — | — | 0.4 mi |
Source: EPA Toxic Release Inventory (TRI) 2023
Flood & disaster history
Christian County has experienced 1 federally declared disaster since 2005. 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. | 0.0 | 15 | ppb | Inorganic | Safe |
Lead level trend (90th percentile)
See how Assumption compares by contaminant
Explore where Assumption ranks among all Illinois cities for specific contaminants.
Water source & infrastructure
Where Assumption's water comes from
Assumption's drinking water is drawn from underground aquifers through wells.
Groundwater is naturally filtered through rock and soil layers, generally requiring less treatment than surface water. However, it can contain naturally occurring contaminants like arsenic, radon, and minerals.
Agricultural activity, septic systems, and industrial operations near well fields can introduce nitrates, pesticides, and volatile organic compounds.
The system is operated by local government ownership and serves approximately 1,315 people through 1 water system.
Water systems serving Assumption
| System Name | PWSID | Population | Source |
|---|---|---|---|
| ASSUMPTION | IL0210050 | 1,315 | GW |
How Assumption compares
Full Illinois rankings →Assumption's score of 65/100 is above the average of 56/100 among major Illinois cities. It outscores 7 of 10 nearby cities.
Nearby cities
View Illinois rankings →About Assumption, IL
Wikipedia →Assumption is a city in Christian County, Illinois, United States. The population was 1,155 as of the 2020 census.
Learn more about your water
Guides and resources related to Assumption's water quality findings.
Explore water quality across Christian
Frequently asked questions
Is Assumption, IL tap water safe to drink?
Assumption's water quality earned a grade of C+ (65/100). Some concerns have been identified. Consider a water filter for an extra layer of protection. The city ranks #781 out of 891 cities tested in Illinois.
What contaminants are in Assumption's water?
Lead was measured at 0.0 ppb (90th percentile). 19 violations are on record.
How is Assumption'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 Assumption?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Assumption's water come from?
Assumption's water is sourced from Groundwater. The city has 1 water system serving approximately 1,315 residents.
What health violations has Assumption's water system had?
Assumption has 4 health-based violations on record. The most recent violation was recorded in October 2025. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 9 violations remain unresolved.
Is Assumption's groundwater at risk of contamination?
Assumption 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 19 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 Assumption's water compare to other cities?
Assumption ranks #781 out of 891 cities in Illinois (better than 12% of state cities) and #11593 out of 15744 cities nationally (26th percentile). The grade of C+ reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.
Does Assumption's small water system affect quality?
Assumption's system serves approximately 1,315 residents. Small community water systems (under 3,300 people) may have fewer financial resources for infrastructure upgrades and advanced treatment technologies. However, they are held to the same EPA drinking water standards as larger systems. This system has 19 violations on record.