Is Somonauk, IL Tap Water Safe to Drink?
Graded A-, with 4 unresolved violations on record. See what was cited — and what it means for your tap. What to do next ↓
88.9/100
waterverge.com Somonauk, IL — Water Quality Report
Somonauk's drinking water received a grade of A- (88.9 out of 100), indicating good water quality. The city's 2 water systems serve approximately 1,936 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 7 violations on record, including 2 health-based violations. 4 remain unresolved.
What to know about Somonauk's water
Somonauk ranks #197 out of 891 cities in Illinois for water quality, placing it above average in the state.
Somonauk 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, Somonauk may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
Water quality score
See methodology →Is Somonauk, IL water safe to drink?
Somonauk's drinking water has significant quality concerns based on EPA testing data. With a grade of A- (88.9/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 2 water systems serve approximately 1,936 residents using groundwater (wells).
Recent water quality updates for Somonauk
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Somonauk's water quality assessment. Grade: A- (88.9/100).
Federal disaster declaration (FEMA DR-4116). Flood event — may have impacted local water infrastructure.
Contaminants: Consumer Confidence Rule.
Federal disaster declaration (FEMA DR-3230). Hurricane event — may have impacted local water infrastructure.
1 health-based. Contaminants: Lead and Copper Rule.
1 health-based. Contaminants: Lead and Copper Rule.
Key contaminant findings
Based on the most recent EPA sampling data for Somonauk's water supply.
Well within EPA limits.
Violation history
Somonauk's water system has 7 total violations on record, including 2 health-based violations. 4 remain unresolved.
Flood & environmental risk
DeKalb County has experienced 4 federally declared disasters since 1973. 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 Somonauk's water come from?
Somonauk's drinking water comes from groundwater (wells), supplied by 2 water systems serving approximately 1,936 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate.
What Somonauk residents can do
Recommended: NSF-certified water filter. This addresses the specific contaminants found in Somonauk'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.
Somonauk's area has a history of flooding. After severe weather, watch for boil water advisories from your local utility.
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 Somonauk
Industrial polluters nearby
Reported releases to surface water by facilities near Somonauk, ranked by pounds discharged annually.
| Facility | Top chemical | To surface water (lbs/yr) | Distance |
|---|---|---|---|
PLANO METAL SPECIALTIES INC PLANO, IL60545 | — | — | 9.4 mi |
DURO CAST INC SOMONAUK, IL60552 | — | — | 0.2 mi |
Source: EPA Toxic Release Inventory (TRI) 2023
Flood & disaster history
DeKalb County has experienced 4 federally declared disasters since 1973. 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 Somonauk compares by contaminant
Explore where Somonauk ranks among all Illinois cities for specific contaminants.
Water source & infrastructure
Where Somonauk's water comes from
Somonauk'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 1,936 people through 2 water systems.
Water systems serving Somonauk
| System Name | PWSID | Population | Source |
|---|---|---|---|
| SOMONAUK | IL0374870 | 1,786 | GW |
| BUCK LAKE ESTATES SUBDIVISION | IL0375100 | 150 | GW |
How Somonauk compares
Full Illinois rankings →Somonauk's score of 88.9/100 is above the average of 56/100 among major Illinois cities. It outscores 9 of 10 nearby cities.
Nearby cities
View Illinois rankings →About Somonauk, IL
Wikipedia →Somonauk is a village in DeKalb and LaSalle Counties in the U.S. state of Illinois. The population was 1,786 at the 2020 Census, down from 1,893 at the 2010 Census.
Learn more about your water
Guides and resources related to Somonauk's water quality findings.
Explore water quality across Dekalb
Frequently asked questions
Is Somonauk, IL tap water safe to drink?
Somonauk's water quality earned a grade of A- (88.9/100). The water generally meets EPA standards and is considered safe for consumption. The city ranks #197 out of 891 cities tested in Illinois.
What contaminants are in Somonauk's water?
Lead was measured at 0.0 ppb (90th percentile). 7 violations are on record.
How is Somonauk'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 Somonauk?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Somonauk's water come from?
Somonauk's water is sourced from Groundwater. The city has 2 water systems serving approximately 1,936 residents.
What health violations has Somonauk's water system had?
Somonauk has 2 health-based violations on record. The most recent violation was recorded in July 2007. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 4 violations remain unresolved.
Is Somonauk's groundwater at risk of contamination?
Somonauk 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 7 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 Somonauk's water compare to other cities?
Somonauk ranks #197 out of 891 cities in Illinois (better than 78% of state cities) and #3169 out of 15744 cities nationally (80th percentile). The grade of A- reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.