Water Quality in Waukesha, WI: 92 Violations — Grade C
Grade C · Score 55/100 · 5 water systems · Updated 2026-05-03
Waukesha'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
On record with EPA: Waukesha, WI has 92 water violations.
Water Quality by ZIP Code in Waukesha
Water quality varies across Waukesha's 4 ZIP codes. Check your specific ZIP for detailed contaminant data.
| ZIP Code | Grade | Score | Violations | Health | |
|---|---|---|---|---|---|
| 53187 | F | 36 | 23 | 12 | View report → |
| 53186 | D | 41 | 23 | 12 | View report → |
| 53188 | D | 41 | 23 | 12 | View report → |
| 53189 | D | 46 | 23 | 12 | View report → |
Violation Trend
EPA violations recorded for water systems serving Waukesha.
Water Quality Overview
Waukesha, Wisconsin receives a water quality grade of C with an overall score of 55 out of 100, based on EPA compliance data from the Safe Drinking Water Information System (SDWIS).
The 5 water systems serving Waukesha have accumulated 92 EPA violations, including 48 health-based violations. These violations are tracked across 4 ZIP codes serving approximately 72,248 people.
What Grade C Means
A grade of C indicates moderate compliance issues. Waukesha'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 Waukesha water systems is 0.0023 mg/L — within EPA limits. No ZIP codes exceed the EPA lead action level.
With 60% of homes built before 1986, Waukesha 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
Waukesha is in EPA Radon Zone 2 (Moderate risk). Testing is recommended, especially for homes with basements or ground-level living spaces.
Water Systems Serving Waukesha
Waukesha is served by 5 community water systems regulated under the Safe Drinking Water Act. These systems collectively serve approximately 72,248 people across 4 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 40 enforcement actions against water systems serving Waukesha. Enforcement actions range from informal compliance assistance to formal orders and penalties.
How to Check Your Water in Waukesha
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 Waukesha Water Systems
The following contaminants have been detected or caused violations across Waukesha's water systems:
| Contaminant | Category | MCL | Violations | ZIPs Affected | Health-Based |
|---|---|---|---|---|---|
| Gross Alpha | Radionuclides | 15 pCi/L | 32 | 4 | Yes |
| Lead and Copper Rule | Treatment Technique | N/A | 24 | 4 | No |
| Gross Beta | Radionuclides | 50 pCi/L | 16 | 4 | Yes |
| Stage 1 DBP Rule | Treatment Technique | N/A | 8 | 4 | No |
| Haloacetic Acids (HAA5) | Disinfection Byproducts | 0.06 mg/L | 4 | 4 | No |
| Surface Water Treatment Rule | Treatment Technique | N/A | 4 | 4 | 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 Waukesha:
| Year | Total Violations | Health-Based |
|---|---|---|
| 2022 | 32 | 32 |
| 2023 | 24 | 24 |
| 2024 | 4 | 4 |
Violations have decreased from 32 in 2022 to 4 in 2024, indicating improving compliance.
EPA Enforcement History
The EPA and state regulators have taken 10 enforcement actions against water systems serving Waukesha. Recent actions:
| Date | Action Type |
|---|---|
| 2025-08-07 | State Order Extension |
| 2025-07-30 | State Informal Action |
| 2025-07-30 | State Order Extension |
| 2025-07-01 | State Informal Action |
| 2025-03-10 | State Order Extension |
| 2024-11-25 | State Informal Action |
| 2024-11-25 | State Informal Enforcement |
| 2024-02-29 | State Formal Action |
| 2024-01-24 | State Informal Action |
| 2024-01-24 | State Order Extension |
Enforcement actions range from informal compliance assistance to formal orders and penalties. The most recent action was on 2025-08-07.
Waukesha vs. Nearby Wisconsin Cities
How Waukesha's water quality compares to similar cities in Wisconsin:
| City | Grade | Violations | Systems | Population |
|---|---|---|---|---|
| Waukesha | C | 92 | 5 | 72,248 |
| Eau Claire | B | 21 | 5 | 71,603 |
| Oshkosh | C | 60 | 4 | 67,076 |
| Janesville | D | 20 | 3 | 65,913 |
Water Quality by ZIP Code in Waukesha
Water quality varies across Waukesha's ZIP codes. The table below shows the worst-scoring and best-scoring areas:
| ZIP Code | Score | Grade | Violations | Health-Based |
|---|---|---|---|---|
| 53187 | 36 | F | 23 | 12 |
| 53186 | 41 | D | 23 | 12 |
| 53188 | 41 | D | 23 | 12 |
| 53189 | 46 | D | 23 | 12 |
Common Questions About Waukesha Water
These are the most common questions residents search for about water quality in Waukesha, Wisconsin:
Is Waukesha water hard or soft? Water hardness varies by source. Waukesha's 5 water systems use multiple sources. Check your ZIP code report for specific hardness data.
Can I drink Waukesha tap water? Waukesha's water receives a grade of C (55/100). There are 48 health-based violations — consider filtration.
What is the best water filter for Waukesha? A NSF/ANSI 53-certified filter for lead removal is a good general choice. See our Water Filter Matcher for personalized recommendations.
Waukesha vs. Wisconsin Average
Understanding how Waukesha 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 Waukesha.
ZIP Codes in Waukesha
Waukesha spans 4 ZIP codes. The ZIP with the lowest water quality score is 53186. 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.