C49/100
Green Lake Tap Water Quality: Is It Safe to Drink? (2026 Report)
Serving 1,002 residents · Wisconsin
What's In Green Lake'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) | 0.001 mg/L | 0.015 mg/L | Above Goal |
EPA Violation History
5
Violations (last 5yr)
0
Unresolved
1
Health-Related
TIER 2Resolved
Treatment technique violation
When: October 17, 2024 – May 29, 2025Rule: Ground Water RuleEnforcement: Resolving — corrective action underway
TIER 3Resolved
Disinfection byproduct treatment technique failure
When: October 17, 2024 – April 7, 2025Rule: Ground Water RuleEnforcement: Resolving — corrective action underway
TIER 3Resolved
Monitoring / Reporting Violation
This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.
When: January 1, 2024 – January 12, 2024Rule: Ground Water RuleEnforcement: Resolving — corrective action underway
TIER 3Resolved
Surface water treatment technique failure
When: July 1, 2022 – October 14, 2022Enforcement: Resolving — corrective action underway
TIER 3Resolved
Surface water treatment technique failure
When: July 1, 2022 – October 14, 2022Enforcement: 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
GREEN LAKE WATERWORKS
Population Served
1,002
Water Source
Groundwater
System ID
WI4240217
Frequently Asked Questions About Green Lake Water
Is Green Lake tap water safe to drink?
Green Lake, Wisconsin tap water receives a grade of C (49/100), which is considered fair. 0 contaminant(s) exceed EPA maximum contaminant levels and 28 violation(s) are on record. Residents should consider using an NSF-certified water filter to reduce contaminant exposure.
What contaminants are in Green Lake's water?
Of the 1 contaminants tested in Green Lake'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 Green Lake have any water quality violations?
Yes, Green Lake has 28 EPA violation(s) on record, with the most recent in 2024. Violation types include TT, Other, MR. 5 of these are health-based violations, which are the most serious category.
Do I need a water filter in Green Lake?
Green Lake 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 Green Lake's tap water come from?
Green Lake's drinking water is sourced from groundwater and supplied by GREEN LAKE WATERWORKS. The system serves approximately 1,002 people. Groundwater is pumped from underground aquifers, which often provides natural filtration.
How often is Green Lake'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. Green Lake'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 Green Lake's water compare to other cities in Wisconsin?
Green Lake'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 Green Lake's water quality?
If you have concerns about Green Lake'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 (GREEN LAKE 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.