Water Quality in Lake Delton, WI: 2 Violations — Grade B
Grade B · Score 82/100 · 2 water systems · Updated 2026-05-03
Lake Delton's water is mostly safe. Minor violations exist but are primarily monitoring-related.
Data: EPA Safe Drinking Water Information System (SDWIS) Last verified: 2026-05-03
Lake Delton, WI has 2 violations in the EPA compliance history — breakdown below.
Water Quality by ZIP Code in Lake Delton
Water quality varies across Lake Delton's 1 ZIP codes. Check your specific ZIP for detailed contaminant data.
| ZIP Code | Grade | Score | Violations | Health | |
|---|---|---|---|---|---|
| 53940 | B | 82 | 2 | 0 | View report → |
Water Quality Overview
Lake Delton, Wisconsin receives a water quality grade of B with an overall score of 82 out of 100, based on EPA compliance data from the Safe Drinking Water Information System (SDWIS).
The 2 water systems serving Lake Delton have accumulated 2 EPA violations (all monitoring/reporting type). These violations are tracked across 1 ZIP codes serving approximately 2,989 people.
What Grade B Means
A grade of B indicates good compliance with EPA drinking water standards. While not perfect, Lake Delton's water systems meet the vast majority of federal requirements. Minor violations may exist but typically relate to monitoring or reporting rather than health-based standards.
Lead Levels
The average 90th percentile lead level across Lake Delton water systems is 0.0011 mg/L — within EPA limits. No ZIP codes exceed the EPA lead action level.
Radon Risk
Lake Delton is in EPA Radon Zone 2 (Moderate risk). Testing is recommended, especially for homes with basements or ground-level living spaces.
Water Systems Serving Lake Delton
Lake Delton is served by 2 community water systems regulated under the Safe Drinking Water Act. These systems collectively serve approximately 2,989 people across 1 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 2 enforcement actions against water systems serving Lake Delton. Enforcement actions range from informal compliance assistance to formal orders and penalties.
How to Check Your Water in Lake Delton
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 Lake Delton Water Systems
The following contaminants have been detected or caused violations across Lake Delton's water systems:
| Contaminant | Category | MCL | Violations | ZIPs Affected | Health-Based |
|---|---|---|---|---|---|
| Surface Water Treatment Rule | Treatment Technique | N/A | 2 | 1 | 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 2 enforcement actions against water systems serving Lake Delton. Recent actions:
| Date | Action Type |
|---|---|
| 2025-09-30 | State Informal Action |
| 2025-08-01 | State Order Extension |
Enforcement actions range from informal compliance assistance to formal orders and penalties. The most recent action was on 2025-09-30.
Lake Delton vs. Nearby Wisconsin Cities
How Lake Delton's water quality compares to similar cities in Wisconsin:
| City | Grade | Violations | Systems | Population |
|---|---|---|---|---|
| Lake Delton | B | 2 | 2 | 2,989 |
| Park Falls | B | 0 | 1 | 2,993 |
| Oconto Falls | C | 2 | 2 | 2,972 |
| Amery | B | 4 | 1 | 2,962 |
Common Questions About Lake Delton Water
These are the most common questions residents search for about water quality in Lake Delton, Wisconsin:
Is Lake Delton water hard or soft? Water hardness varies by source. Lake Delton's 2 water systems use multiple sources. Check your ZIP code report for specific hardness data.
Can I drink Lake Delton tap water? Lake Delton's water receives a grade of B (82/100). No health-based violations have been recorded, but home testing is always recommended.
What is the best water filter for Lake Delton? A NSF/ANSI 53-certified filter for lead removal is a good general choice. See our Water Filter Matcher for personalized recommendations.
Lake Delton vs. Wisconsin Average
Understanding how Lake Delton 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 Lake Delton.
ZIP Codes in Lake Delton
Lake Delton spans 1 ZIP code. The ZIP with the lowest water quality score is 53940. 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.
Frequently Asked Questions
Your Water is Safe — Here's How to Keep It That Way
Grade B is excellent news. Here's what proactive homeowners do to maintain water quality:
Annual Water Testing
EPA recommends annual testing even with clean water. Home test kits: $20-$50. Catches changes before they become problems.
Maintenance Filtration
A basic carbon filter removes chlorine taste and catches emerging contaminants like PFAS that aren't yet fully regulated.
Plumbing Check
Even safe city water picks up lead from home pipes. If your home was built before 1986, a one-time pipe inspection is recommended.