Is Windsor, WI 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 ↓
89.5/100
waterverge.com Windsor, WI — Water Quality Report
Windsor's drinking water received a grade of A- (89.5 out of 100), indicating good water quality. The city's 1 water system serves approximately 4,607 residents using groundwater.
Lead levels were measured at 5.5 ppb (90th percentile), which is within EPA limits but above recommended levels. This system has not yet been tested for PFAS under the EPA UCMR 5 program.
The system has 4 violations on record, including 1 health-based violation. 1 remains unresolved.
What to know about Windsor's water
Windsor ranks #93 out of 446 cities in Wisconsin for water quality, placing it above average in the state.
Windsor 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.
While lead levels are within EPA limits, they are above the recommended 5 ppb threshold that health organizations consider ideal. A point-of-use filter adds an extra layer of protection.
Water quality score
See methodology →Is Windsor, WI water safe to drink?
Windsor's tap water meets most EPA standards but has areas that warrant attention. With a grade of A- (89.5/100), some contaminant levels or compliance issues suggest that residents may benefit from additional filtration. The city's 1 water system serves approximately 4,607 residents using groundwater (wells).
Recent water quality updates for Windsor
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Windsor's water quality assessment. Grade: A- (89.5/100).
Federal disaster declaration (FEMA DR-4402). Flood event — may have impacted local water infrastructure.
Federal disaster declaration (FEMA DR-3249). Hurricane event — may have impacted local water infrastructure.
1 health-based. Contaminants: Coliform (TCR).
Contaminants: Coliform (TCR).
Key contaminant findings
Based on the most recent EPA sampling data for Windsor's water supply.
Within EPA limits but above the American Academy of Pediatrics recommended level of 1 ppb. An NSF 53-certified filter provides additional protection.
Violation history
Windsor's water system has 4 total violations on record, including 1 health-based violation. 1 remain unresolved.
Flood & environmental risk
Dane County has experienced 3 federally declared disasters since 1976. 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 Yahara River, Sixmile Creek, Sixmile Creek @ County Trnk Hghwy M Nr Waunakee,Wi, Dorn (Spring) Creek @ Ct Highway Q Nr Waunakee, Dorn (Spring) Creek.
Where does Windsor's water come from?
Windsor's drinking water comes from groundwater (wells), supplied by 1 water system serving approximately 4,607 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate. Nearby water bodies include Yahara River (river), Sixmile Creek (river), Sixmile Creek @ County Trnk Hghwy M Nr Waunakee,Wi (river), Dorn (Spring) Creek @ Ct Highway Q Nr Waunakee (river), Dorn (Spring) Creek (river).
What Windsor 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.
Windsor'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 Windsor
Industrial polluters nearby
Reported releases to surface water by facilities near Windsor, ranked by pounds discharged annually.
| Facility | Top chemical | To surface water (lbs/yr) | Distance |
|---|---|---|---|
HOLCIM SOLUTIONS & PRODUCTS (US) LLC DE FOREST, WI53532 | — | — | 2.9 mi |
REG MADISON LLC DE FOREST, WI53532 | — | — | 2.9 mi |
FRANKLIN ELECTRIC FUELING SYSTEMS DEFOREST, WI53532 | — | — | 2.8 mi |
AMERICAN PACKAGING CORP SITE DEFOREST, WI53532 | — | — | 2.7 mi |
THERMAL SPRAY TECHNOLOGIES INC SUN PRAIRIE, WI53590 | — | — | 4.8 mi |
Source: EPA Toxic Release Inventory (TRI) 2023
Flood & disaster history
Dane County has experienced 3 federally declared disasters since 1976. Flooding and severe weather can compromise water treatment infrastructure and introduce contaminants into drinking water supplies.
Recommended water filters
Based on contaminants detected in Windsor'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. | 5.5 | 15 | ppb | Inorganic | Safe |
Lead level trend (90th percentile)
See how Windsor compares by contaminant
Explore where Windsor ranks among all Wisconsin cities for specific contaminants.
Water source & infrastructure
Where Windsor's water comes from
Windsor'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 4,607 people through 1 water system.
Water bodies near Windsor
Windsor is located near 5 notable water bodies. These water bodies contribute to the regional watershed and may indirectly affect groundwater quality.
Water systems serving Windsor
| System Name | PWSID | Population | Source |
|---|---|---|---|
| WINDSOR WATER UTILITY SOUTH | WI1130267 | 4,607 | GW |
How Windsor compares
Full Wisconsin rankings →Windsor's score of 89.5/100 is above the average of 65/100 among major Wisconsin cities. It outscores 8 of 10 nearby cities.
Nearby cities
View Wisconsin rankings →About Windsor, WI
Wikipedia →Windsor is a village in Dane County, Wisconsin, United States. The population was 8,754 at the 2020 census. It is part of the Madison metropolitan area. The unincorporated communities of Lake Windsor, Morrisonville, and Token Creek are located within the village.
Learn more about your water
Guides and resources related to Windsor's water quality findings.
Explore water quality across Dane
Frequently asked questions
Is Windsor, WI tap water safe to drink?
Windsor's water quality earned a grade of A- (89.5/100). The water generally meets EPA standards and is considered safe for consumption. The city ranks #93 out of 446 cities tested in Wisconsin.
What contaminants are in Windsor's water?
Lead was measured at 5.5 ppb (90th percentile). 4 violations are on record.
How is Windsor'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 Windsor?
While lead levels are within EPA limits, a filter adds extra protection. Based on current data, basic filtration should suffice for additional peace of mind.
Where does Windsor's water come from?
Windsor's water is sourced from Groundwater. The city has 1 water system serving approximately 4,607 residents.
What health violations has Windsor's water system had?
Windsor has 1 health-based violation on record. The most recent violation was recorded in November 1994. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 1 violation remains unresolved.
Is Windsor's groundwater at risk of contamination?
Windsor 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 4 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 Windsor's water compare to other cities?
Windsor ranks #93 out of 446 cities in Wisconsin (better than 79% of state cities) and #2769 out of 15744 cities nationally (82th percentile). The grade of A- reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.