Is Williams Bay, WI Tap Water Safe to Drink?
Graded C — but Lead was detected above EPA limits. Here's what's in the water and how to remove it. What to do next ↓
61.8/100
waterverge.com Williams Bay, WI — Water Quality Report
Williams Bay's drinking water received a grade of C (61.8 out of 100), indicating fair water quality. The city's 1 water system serves approximately 2,601 residents using groundwater.
Lead levels were measured at 16.0 ppb (90th percentile), which exceeds the EPA action level of 15 ppb. This system has not yet been tested for PFAS under the EPA UCMR 5 program.
The system has 45 violations on record, including 1 health-based violation. 11 remain unresolved.
What to know about Williams Bay's water
Williams Bay ranks #380 out of 446 cities in Wisconsin for water quality, placing it among the lowest-rated in the state.
Williams Bay 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.
Lead levels exceed the EPA action level of 15 ppb, which typically indicates aging lead service lines or lead solder in the distribution system. An NSF 53-certified filter is strongly recommended for drinking and cooking water.
As a small community water system, Williams Bay may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
The system has seen 7 violations in the past five years, suggesting a pattern of compliance challenges that residents should monitor closely.
Water quality score
See methodology →Is Williams Bay, WI water safe to drink?
Williams Bay's drinking water has significant quality concerns based on EPA testing data. With a grade of C (61.8/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 1 water system serves approximately 2,601 residents using groundwater (wells).
Recent water quality updates for Williams Bay
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Williams Bay's water quality assessment. Grade: C (61.8/100).
Contaminants: Public Notice.
1 health-based. Contaminants: Lead and Copper Rule.
Contaminants: Lead and Copper Rule.
Federal disaster declaration (FEMA DR-3249). Hurricane event — may have impacted local water infrastructure.
Federal disaster declaration (FEMA DR-496). Flood event — may have impacted local water infrastructure.
Key contaminant findings
Based on the most recent EPA sampling data for Williams Bay's water supply.
Exceeds EPA action level. Lead service line replacement and point-of-use filtration recommended.
Violation history
Williams Bay's water system has 45 total violations on record, including 1 health-based violation. 11 remain unresolved. 7 violations were issued in the last 5 years.
Flood & environmental risk
Walworth County has experienced 3 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 Jackson Creek, Delavan Lake Inlet, Delavan Lake Outlet, Piscasaw Creek, White River.
Where does Williams Bay's water come from?
Williams Bay's drinking water comes from groundwater (wells), supplied by 1 water system serving approximately 2,601 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate. Nearby water bodies include Jackson Creek (river), Delavan Lake Inlet (river), Delavan Lake Outlet (river), Piscasaw Creek (river), White River (river).
What Williams Bay residents can do
Recommended: NSF 53-certified pitcher or under-sink filter. This addresses the specific contaminants found in Williams Bay'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.
Williams Bay'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 Williams Bay
Industrial polluters nearby
Reported releases to surface water by facilities near Williams Bay, ranked by pounds discharged annually.
| Facility | Top chemical | To surface water (lbs/yr) | Distance |
|---|---|---|---|
CONAGRA FOODS PACKAGED FOODS LLC DARIEN, WI53114 | — | — | 9.7 mi |
USG STRUCTURAL TECHNOLOGIES LLC DELAVAN, WI53115 | — | — | 5.4 mi |
PENTAIR FLOW TECHNOLOGIES DELAVAN, WI53115 | — | — | 5.5 mi |
SPX FLOW US LLC DELAVAN, WI53115 | — | — | 6.0 mi |
SPX FLOW US LLC DELAVAN, WI53115 | — | — | 5.2 mi |
Source: EPA Toxic Release Inventory (TRI) 2023
Superfund sites within 10 miles of Williams Bay
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.
- DELAVAN MUNICIPAL WELL 45.4 mi
Source: EPA Superfund National Priorities List
Flood & disaster history
Walworth County has experienced 3 federally declared disasters since 1973. Flooding and severe weather can compromise water treatment infrastructure and introduce contaminants into drinking water supplies.
Recommended water filters
Based on contaminants detected in Williams Bay'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. | 16.0 | 15 | ppb | Inorganic | Over Limit |
Lead level trend (90th percentile)
See how Williams Bay compares by contaminant
Explore where Williams Bay ranks among all Wisconsin cities for specific contaminants.
Water source & infrastructure
Where Williams Bay's water comes from
Williams Bay'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 2,601 people through 1 water system.
Water bodies near Williams Bay
Williams Bay is located near 5 notable water bodies. These water bodies contribute to the regional watershed and may indirectly affect groundwater quality.
Water systems serving Williams Bay
| System Name | PWSID | Population | Source |
|---|---|---|---|
| WILLIAMS BAY WATERWORKS | WI2650060 | 2,601 | GW |
How Williams Bay compares
Full Wisconsin rankings →Williams Bay's score of 61.8/100 is on par with the average of 65/100 among major Wisconsin cities. It outscores 5 of 10 nearby cities.
Nearby cities
View Wisconsin rankings →About Williams Bay, WI
Wikipedia →Williams Bay is a village in Walworth County, Wisconsin, United States. It is one of three municipalities on Geneva Lake. The population was 2,953 at the 2020 census. On June 22, 2024 the town was hit by an EF-1 tornado, there were no injuries or fatalities, but the storm caused some areas of considerable damage.
Learn more about your water
Guides and resources related to Williams Bay's water quality findings.
Explore water quality across Walworth
Frequently asked questions
Is Williams Bay, WI tap water safe to drink?
Williams Bay's water quality earned a grade of C (61.8/100). Some concerns have been identified. Consider a water filter for an extra layer of protection. The city ranks #380 out of 446 cities tested in Wisconsin.
What contaminants are in Williams Bay's water?
Lead was measured at 16.0 ppb (90th percentile). 45 violations are on record.
How is Williams Bay'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 Williams Bay?
Yes — lead levels exceed the EPA action level of 15 ppb. We recommend an NSF 53-certified filter or reverse osmosis system. Based on current data, basic filtration should suffice for additional peace of mind.
Where does Williams Bay's water come from?
Williams Bay's water is sourced from Groundwater. The city has 1 water system serving approximately 2,601 residents.
What health violations has Williams Bay's water system had?
Williams Bay has 1 health-based violation on record. The most recent violation was recorded in September 2025. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 11 violations remain unresolved.
Is Williams Bay's groundwater at risk of contamination?
Williams Bay 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 45 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 Williams Bay's water compare to other cities?
Williams Bay ranks #380 out of 446 cities in Wisconsin (better than 15% of state cities) and #11954 out of 15744 cities nationally (24th percentile). The grade of C reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.
Does Williams Bay's small water system affect quality?
Williams Bay's system serves approximately 2,601 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 45 violations on record.