Is Winnebago, IL Tap Water Safe to Drink?
Graded A, with 1 unresolved violation on record. See what was cited — and what it means for your tap. What to do next ↓
93.2/100
waterverge.com Winnebago, IL — Water Quality Report
Winnebago's drinking water received a grade of A (93.2 out of 100), indicating excellent water quality. The city's 1 water system serves approximately 3,000 residents using groundwater.
Lead levels were measured at 4.6 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 27 violations on record, including 2 health-based violations. 1 remains unresolved.
What to know about Winnebago's water
Winnebago ranks #47 out of 891 cities in Illinois for water quality, placing it one of the best in the state.
Winnebago 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, Winnebago may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
Water quality score
See methodology →Is Winnebago, IL water safe to drink?
Winnebago's tap water meets most EPA standards but has areas that warrant attention. With a grade of A (93.2/100), some contaminant levels or compliance issues suggest that residents may benefit from additional filtration. The city's 1 water system serves approximately 3,000 residents using groundwater (wells).
Recent water quality updates for Winnebago
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Winnebago's water quality assessment. Grade: A (93.2/100).
Federal disaster declaration (FEMA DR-4819). Flood event — may have impacted local water infrastructure.
Federal disaster declaration (FEMA DR-4116). Flood event — may have impacted local water infrastructure.
Contaminants: Xylenes, Total, DICHLOROMETHANE, o-Dichlorobenzene.
1 health-based. Contaminants: Coliform (TCR).
Contaminants: Coliform (TCR).
Key contaminant findings
Based on the most recent EPA sampling data for Winnebago's water supply.
Well within EPA limits.
Violation history
Winnebago's water system has 27 total violations on record, including 2 health-based violations. 1 remain unresolved.
Flood & environmental risk
Winnebago County has experienced 6 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. Local water sources include Rock River Above Dam, Rock River.
Where does Winnebago's water come from?
Winnebago's drinking water comes from groundwater (wells), supplied by 1 water system serving approximately 3,000 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate. Nearby water bodies include Rock River Above Dam (river), Rock River (river).
What Winnebago 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.
Run cold water for 30 seconds before drinking, especially in the morning. Lead and copper leach from household plumbing when water sits in pipes.
Winnebago'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 Winnebago
Industrial polluters nearby
Reported releases to surface water by facilities near Winnebago, ranked by pounds discharged annually.
Total reported releases to surface water: 106 lbs
| Facility | Top chemical | To surface water (lbs/yr) | Distance |
|---|---|---|---|
GUNITE CORP ROCKFORD, IL61104 | Manganese | 106 | 7.5 mi |
QUALITY METAL FINISHING CO BYRON, IL61010 | — | — | 9.6 mi |
ARNTZEN CORP ROCKFORD, IL61101 | — | — | 6.8 mi |
FOREST CITY TECHNOLOGIES - ROCKFORD PLANT ROCKFORD, IL61102 | — | — | 6.6 mi |
K & J FINISHING ROCKFORD, IL61102 | — | — | 6.7 mi |
Source: EPA Toxic Release Inventory (TRI) 2023
Superfund sites within 10 miles of Winnebago
Superfund sites nearby
Federally tracked hazardous-waste sites on the EPA National Priorities List. Proximity does not necessarily indicate tap-water contamination — the connection depends on hydrology and treatment.
- INTERSTATE POLLUTION CONTROL INC7.2 mi
- SOUTHEAST ROCKFORD GROUND WATER CONTAMINATION8.7 mi
Source: EPA Superfund National Priorities List
Flood & disaster history
Winnebago County has experienced 6 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. | 4.6 | 15 | ppb | Inorganic | Safe |
Lead level trend (90th percentile)
See how Winnebago compares by contaminant
Explore where Winnebago ranks among all Illinois cities for specific contaminants.
Water source & infrastructure
Where Winnebago's water comes from
Winnebago'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 3,000 people through 1 water system.
Water bodies near Winnebago
Winnebago is located near 2 notable water bodies. These water bodies contribute to the regional watershed and may indirectly affect groundwater quality.
Water systems serving Winnebago
| System Name | PWSID | Population | Source |
|---|---|---|---|
| WINNEBAGO | IL2010500 | 3,000 | GW |
How Winnebago compares
Full Illinois rankings →Winnebago's score of 93.2/100 is above the average of 56/100 among major Illinois cities. It outscores 10 of 10 nearby cities.
Nearby cities
View Illinois rankings →About Winnebago, IL
Learn more about your water
Guides and resources related to Winnebago's water quality findings.
Explore water quality across Winnebago
Frequently asked questions
Is Winnebago, IL tap water safe to drink?
Winnebago's water quality earned a grade of A (93.2/100). The water generally meets EPA standards and is considered safe for consumption. The city ranks #47 out of 891 cities tested in Illinois.
What contaminants are in Winnebago's water?
Lead was measured at 4.6 ppb (90th percentile). 27 violations are on record.
How is Winnebago'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 Winnebago?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Winnebago's water come from?
Winnebago's water is sourced from Groundwater. The city has 1 water system serving approximately 3,000 residents.
What health violations has Winnebago's water system had?
Winnebago has 2 health-based violations on record. The most recent violation was recorded in October 2002. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 1 violation remains unresolved.
Is Winnebago's groundwater at risk of contamination?
Winnebago 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 27 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 Winnebago's water compare to other cities?
Winnebago ranks #47 out of 891 cities in Illinois (better than 95% of state cities) and #931 out of 15744 cities nationally (94th percentile). The grade of A reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.
Does Winnebago's small water system affect quality?
Winnebago's system serves approximately 3,000 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 27 violations on record.