Water Quality in Fond Du Lac, WI: 39 Violations — Grade D
Grade D · Score 46/100 · 5 water systems · Updated 2026-05-03
Fond Du Lac's water has significant violations. Water testing and filtration are recommended.
Data: EPA Safe Drinking Water Information System (SDWIS) Last verified: 2026-05-03
Reviewing EPA compliance files for Fond Du Lac, WI surfaces 39 documented water violations — each categorized by violation type and linked to the utility that drew the federal citation.
Water Quality by ZIP Code in Fond Du Lac
Water quality varies across Fond Du Lac's 3 ZIP codes. Check your specific ZIP for detailed contaminant data.
| ZIP Code | Grade | Score | Violations | Health | |
|---|---|---|---|---|---|
| 54935 | D | 42 | 13 | 2 | View report → |
| 54937 | D | 47 | 13 | 2 | View report → |
| 54936 | D | 49 | 13 | 2 | View report → |
Water Quality Overview
Fond Du Lac, Wisconsin receives a water quality grade of D with an overall score of 46 out of 100, based on EPA compliance data from the Safe Drinking Water Information System (SDWIS).
The 5 water systems serving Fond Du Lac have accumulated 39 EPA violations, including 6 health-based violations. These violations are tracked across 3 ZIP codes serving approximately 46,460 people.
What Grade D Means
A grade of D indicates significant compliance issues. Fond Du Lac's water systems have accumulated violations that suggest ongoing water quality challenges. Residents should check their specific ZIP code report and consider water testing or filtration.
Lead Levels
The average 90th percentile lead level across Fond Du Lac water systems is 0.0095 mg/L — within EPA limits. No ZIP codes exceed the EPA lead action level.
With 62% of homes built before 1986, Fond Du Lac has a higher-than-average risk of lead from older plumbing. Lead solder was banned in 1986, and homes built before this date may have lead in pipes, solder joints, or fixtures.
Radon Risk
Fond Du Lac is in EPA Radon Zone 1 (High risk). The EPA recommends all homes in Zone 1 areas be tested for radon. Radon is the second leading cause of lung cancer after smoking.
Water Systems Serving Fond Du Lac
Fond Du Lac is served by 5 community water systems regulated under the Safe Drinking Water Act. These systems collectively serve approximately 46,460 people across 3 ZIP codes.
Each water system is identified by a Public Water System ID (PWSID) and is required to:
- Test for over 90 regulated contaminants on a regular schedule
- Report results to the EPA and state regulators
- Issue an annual Consumer Confidence Report (CCR) to all customers
- Take corrective action when violations occur
The EPA has taken 30 enforcement actions against water systems serving Fond Du Lac. Enforcement actions range from informal compliance assistance to formal orders and penalties.
How to Check Your Water in Fond Du Lac
Enter your ZIP code on ZipCheckup to see your specific water system data, including contaminant levels, violation history, and safety scores
Request your CCR — your water utility must provide an annual Consumer Confidence Report with detailed test results for all monitored contaminants
Get a home test — certified kits cost $20–$50 and test for lead, bacteria, and common contaminants. Professional lab tests ($150–$400) cover a broader panel
Consider filtration — NSF-certified filters can remove specific contaminants. Reverse osmosis removes the broadest range; activated carbon is effective for chlorine and many organics
Check for advisories — monitor your local utility website and local news for boil water advisories or system alerts
Contaminants Detected in Fond Du Lac Water Systems
The following contaminants have been detected or caused violations across Fond Du Lac's water systems:
| Contaminant | Category | MCL | Violations | ZIPs Affected | Health-Based |
|---|---|---|---|---|---|
| Stage 2 DBP Rule | Treatment Technique | N/A | 9 | 3 | Yes |
| Lead and Copper Rule | Treatment Technique | N/A | 6 | 3 | No |
| Stage 1 DBP Rule | Treatment Technique | N/A | 3 | 3 | No |
| Lead | Inorganic | 0.015 mg/L | 3 | 3 | No |
| Total Coliform | Microbiological | N/A | 3 | 3 | No |
MCL = Maximum Contaminant Level (EPA enforceable standard). Health-based violations indicate levels that may pose direct health risks.
EPA Enforcement History
The EPA and state regulators have taken 10 enforcement actions against water systems serving Fond Du Lac. Recent actions:
| Date | Action Type |
|---|---|
| 2025-09-10 | State Order Extension |
| 2025-06-12 | State Informal Action |
| 2025-06-12 | State Order Extension |
| 2025-05-15 | State Informal Action |
| 2025-05-06 | State Informal Action |
| 2025-05-06 | State Order Extension |
| 2025-03-25 | State Order Extension |
| 2024-12-26 | State Order Extension |
| 2024-10-17 | State Order Extension |
| 2021-02-22 | State Order Extension |
Enforcement actions range from informal compliance assistance to formal orders and penalties. The most recent action was on 2025-09-10.
Fond Du Lac vs. Nearby Wisconsin Cities
How Fond Du Lac's water quality compares to similar cities in Wisconsin:
| City | Grade | Violations | Systems | Population |
|---|---|---|---|---|
| Fond Du Lac | D | 39 | 5 | 46,460 |
| Wausau | C | 39 | 5 | 46,762 |
| Eldorado | D | 0 | 1 | 44,303 |
| Rosendale | D | 0 | 1 | 44,303 |
Water Quality by ZIP Code in Fond Du Lac
Water quality varies across Fond Du Lac's ZIP codes. The table below shows the worst-scoring and best-scoring areas:
Common Questions About Fond Du Lac Water
These are the most common questions residents search for about water quality in Fond Du Lac, Wisconsin:
Is Fond Du Lac water hard or soft? Water hardness varies by source. Fond Du Lac's 5 water systems use multiple sources. Check your ZIP code report for specific hardness data.
Can I drink Fond Du Lac tap water? Fond Du Lac's water receives a grade of D (46/100). There are 6 health-based violations — consider filtration.
What is the best water filter for Fond Du Lac? A NSF/ANSI 53-certified filter for lead removal is a good general choice. See our Water Filter Matcher for personalized recommendations.
Fond Du Lac vs. Wisconsin Average
Understanding how Fond Du Lac compares to the broader Wisconsin average helps contextualize your local water quality. Factors like water source, treatment methods, and infrastructure age all contribute to differences between cities in the same state.
To see how individual neighborhoods compare, check the ZIP code reports below — water quality can vary significantly even within Fond Du Lac.
ZIP Codes in Fond Du Lac
Fond Du Lac spans 3 ZIP codes. The ZIP with the lowest water quality score is 54935. Each ZIP code has its own water quality profile based on the specific water system serving that area. Check each ZIP code for detailed contaminant data, violation history, and system information.
Data Sources
- Water quality: EPA Safe Drinking Water Information System (SDWIS)
- Lead/copper: EPA Lead and Copper Rule sampling data
- Radon: EPA Map of Radon Zones
- Enforcement: EPA ECHO database
- Filter recommendations: NSF/ANSI certified products
Updated daily.