Water Quality in Delafield, WI: 14 Violations — Grade C
Grade C · Score 67/100 · 5 water systems · Updated 2026-05-03
Delafield's water has moderate compliance issues. Residents in affected areas should consider filtration.
Data: EPA Safe Drinking Water Information System (SDWIS) Last verified: 2026-05-03
Federal EPA data for Delafield, WI shows 14 water compliance events in the record — the table below identifies system names and violation types.
Water Quality by ZIP Code in Delafield
Water quality varies across Delafield's 1 ZIP codes. Check your specific ZIP for detailed contaminant data.
| ZIP Code | Grade | Score | Violations | Health | |
|---|---|---|---|---|---|
| 53018 | C | 67 | 14 | 3 | View report → |
Violation Trend
EPA violations recorded for water systems serving Delafield.
Water Quality Overview
Delafield, Wisconsin receives a water quality grade of C with an overall score of 67 out of 100, based on EPA compliance data from the Safe Drinking Water Information System (SDWIS).
The 5 water systems serving Delafield have accumulated 14 EPA violations, including 3 health-based violations. These violations are tracked across 1 ZIP codes serving approximately 1,857 people.
What Grade C Means
A grade of C indicates moderate compliance issues. Delafield's water systems have some violations that warrant attention. While the water may still be safe for most people, residents in affected ZIP codes should consider additional testing or filtration.
Lead Levels
The average 90th percentile lead level across Delafield water systems is 0.0011 mg/L — within EPA limits. No ZIP codes exceed the EPA lead action level.
With 53% of homes built before 1986, Delafield 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
Delafield 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 Delafield
Delafield is served by 5 community water systems regulated under the Safe Drinking Water Act. These systems collectively serve approximately 1,857 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 10 enforcement actions against water systems serving Delafield. Enforcement actions range from informal compliance assistance to formal orders and penalties.
How to Check Your Water in Delafield
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 Delafield Water Systems
The following contaminants have been detected or caused violations across Delafield's water systems:
| Contaminant | Category | MCL | Violations | ZIPs Affected | Health-Based |
|---|---|---|---|---|---|
| Stage 1 DBP Rule | Treatment Technique | N/A | 3 | 1 | No |
| Stage 2 DBP Rule | Treatment Technique | N/A | 2 | 1 | Yes |
| Chlorine residual | Disinfectant | 4 mg/L | 1 | 1 | Yes |
| Revised Total Coliform Rule | Microbiological | N/A | 1 | 1 | No |
| Lead and Copper Rule | Treatment Technique | N/A | 1 | 1 | No |
| Atrazine | Organic | 0.003 mg/L | 1 | 1 | Yes |
| Total Coliform | Microbiological | N/A | 1 | 1 | No |
MCL = Maximum Contaminant Level (EPA enforceable standard). Health-based violations indicate levels that may pose direct health risks.
Violation Trend Over Time
Year-by-year EPA violations recorded for water systems serving Delafield:
| Year | Total Violations | Health-Based |
|---|---|---|
| 2021 | 1 | 1 |
| 2024 | 2 | 2 |
Violations have increased from 1 in 2021 to 2 in 2024. This trend warrants monitoring.
EPA Enforcement History
The EPA and state regulators have taken 10 enforcement actions against water systems serving Delafield. Recent actions:
| Date | Action Type |
|---|---|
| 2025-03-06 | State Order Extension |
| 2025-01-02 | State Order Extension |
| 2025-01-02 | State Informal Action |
| 2024-12-09 | State Order Extension |
| 2023-05-22 | State Informal Action |
| 2022-07-11 | State Order Extension |
| 2022-06-17 | State Informal Action |
| 2022-06-17 | State Informal Enforcement |
| 2022-03-04 | State Informal Action |
| 2022-02-25 | State Informal Action |
Enforcement actions range from informal compliance assistance to formal orders and penalties. The most recent action was on 2025-03-06.
Delafield vs. Nearby Wisconsin Cities
How Delafield's water quality compares to similar cities in Wisconsin:
| City | Grade | Violations | Systems | Population |
|---|---|---|---|---|
| Delafield | C | 14 | 5 | 1,857 |
| Fremont | D | 0 | 1 | 1,856 |
| Weyauwega | C | 1 | 1 | 1,856 |
| Cambridge | C | 3 | 5 | 1,855 |
Common Questions About Delafield Water
These are the most common questions residents search for about water quality in Delafield, Wisconsin:
Is Delafield water hard or soft? Water hardness varies by source. Delafield's 5 water systems use multiple sources. Check your ZIP code report for specific hardness data.
Can I drink Delafield tap water? Delafield's water receives a grade of C (67/100). There are 3 health-based violations — consider filtration.
What is the best water filter for Delafield? A NSF/ANSI 53-certified filter for lead removal is a good general choice. See our Water Filter Matcher for personalized recommendations.
Delafield vs. Wisconsin Average
Understanding how Delafield 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 Delafield.
ZIP Codes in Delafield
Delafield spans 1 ZIP code. The ZIP with the lowest water quality score is 53018. 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.