C49/100
Williams Bay Tap Water Quality: Is It Safe to Drink? (2026 Report)
Serving 2,601 residents · Wisconsin
What's In Williams Bay's Tap Water?
1
Contaminants Tested
0
Exceed EPA Limits
1
Above EPA Goals
1 contaminant above EPA health goals
| Contaminant | Detected | Limit (MCL) | Status |
|---|---|---|---|
Lead (90th percentile) | 0.006 mg/L | 0.015 mg/L | Above Goal |
EPA Violation History
7
Violations (last 5yr)
5
Unresolved
1
Health-Related
TIER 3Unresolved
Disinfection byproduct treatment technique failure
TIER 2Unresolved
Other non-health-based violation
TIER 3Unresolved
Failed to issue initial public notification
This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.
TIER 3Unresolved
Monitoring / Reporting Violation
This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.
TIER 3Unresolved
Monitoring / Reporting Violation
This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.
TIER 3Resolved
Surface water treatment technique failure
When: July 1, 2021 – October 18, 2021Enforcement: Resolving — corrective action underway
TIER 3Resolved
Surface water treatment technique failure
When: July 1, 2021 – October 18, 2021Enforcement: Resolving — corrective action underway
Understanding violation severity
Tier 1Urgent health risk. Utility must notify all customers within 24 hours.Tier 2Important health or treatment issue. Customers notified within 30 days.Tier 3Administrative or monitoring issue. Reported in the annual water quality report.
Source: EPA Safe Drinking Water Information System (SDWIS) · Updated quarterly
Water Utility Details
WILLIAMS BAY WATERWORKS
Population Served
2,601
Water Source
Groundwater
System ID
WI2650060
Frequently Asked Questions About Williams Bay Water
Is Williams Bay tap water safe to drink?
Williams Bay, Wisconsin tap water receives a grade of C (49/100), which is considered fair. 0 contaminant(s) exceed EPA maximum contaminant levels and 44 violation(s) are on record. Residents should consider using an NSF-certified water filter to reduce contaminant exposure.
What contaminants are in Williams Bay's water?
Of the 1 contaminants tested in Williams Bay's water supply, the most notable include Lead (90th percentile). No contaminants exceed EPA legal limits. 1 contaminant(s) exceed EPA health goals (MCLGs), which are non-enforceable targets set at levels with no known health risk.
Does Williams Bay have any water quality violations?
Yes, Williams Bay has 44 EPA violation(s) on record, with the most recent in 2025. Violation types include Other, TT, MR. 1 of these are health-based violations, which are the most serious category.
Do I need a water filter in Williams Bay?
Williams Bay water meets EPA standards, so a filter is not strictly necessary. However, some residents prefer the added security of a water filter. EPA health goals (MCLGs) are stricter than legal limits and are set at levels with zero expected health risk. 1 contaminant(s) exceed these stricter goals.
Where does Williams Bay's tap water come from?
Williams Bay's drinking water is sourced from groundwater and supplied by WILLIAMS BAY WATERWORKS. The system serves approximately 2,601 people. Groundwater is pumped from underground aquifers, which often provides natural filtration.
How often is Williams Bay's water tested?
Under the Safe Drinking Water Act (SDWA), water utilities are required to regularly test for over 90 contaminants. Testing frequency varies by contaminant — some are tested monthly, others quarterly or annually. Williams Bay's water systems must report results to the EPA and publish an annual Consumer Confidence Report (CCR). The data on this page reflects the latest available EPA testing data.
How does Williams Bay's water compare to other cities in Wisconsin?
Williams Bay's water quality score of 49/100 earns a grade of C, which is considered fair. This is a below-average score that indicates room for improvement. Visit our Wisconsin state page to see how all cities in the state compare.
What should I do if I'm concerned about Williams Bay's water quality?
If you have concerns about Williams Bay's tap water, consider these steps: (1) Request your utility's annual Consumer Confidence Report for detailed local data. (2) Get your water independently tested through a state-certified laboratory. (3) Consider an NSF-certified water filter rated for the contaminants found in your area. (4) Contact your water utility (WILLIAMS BAY WATERWORKS) with specific questions. (5) Report water quality issues to your state drinking water program or the EPA Safe Drinking Water Hotline at 800-426-4791.