Water Quality in Green Bay, WI: 72 Violations — Grade B
Grade B · Score 78/100 · 5 water systems · Updated 2026-05-03
Green Bay'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
Drinking water compliance data for Green Bay, WI reflects 72 EPA violations — details in the grid below.
Water Quality Map: Green Bay, WI
Each dot represents a ZIP code. Color indicates water quality grade. Tap a dot for details.
Water Quality by ZIP Code in Green Bay
Water quality varies across Green Bay's 12 ZIP codes. Check your specific ZIP for detailed contaminant data.
| ZIP Code | Grade | Score | Violations | Health | |
|---|---|---|---|---|---|
| 54301 | B | 71 | 6 | 2 | View report → |
| 54302 | B | 71 | 6 | 2 | View report → |
| 54303 | B | 71 | 6 | 2 | View report → |
| 54311 | B | 76 | 6 | 2 | View report → |
| 54313 | B | 76 | 6 | 2 | View report → |
| 54304 | B | 81 | 6 | 2 | View report → |
| 54305 | B | 81 | 6 | 2 | View report → |
| 54306 | B | 81 | 6 | 2 | View report → |
| 54307 | B | 81 | 6 | 2 | View report → |
| 54308 | B | 81 | 6 | 2 | View report → |
| 54324 | B | 81 | 6 | 2 | View report → |
| 54344 | B | 81 | 6 | 2 | View report → |
Violation Trend
EPA violations recorded for water systems serving Green Bay.
Water Quality Overview
Green Bay, Wisconsin receives a water quality grade of B with an overall score of 78 out of 100, based on EPA compliance data from the Safe Drinking Water Information System (SDWIS).
The 5 water systems serving Green Bay have accumulated 72 EPA violations, including 24 health-based violations. These violations are tracked across 12 ZIP codes serving approximately 177,103 people.
What Grade B Means
A grade of B indicates good compliance with EPA drinking water standards. While not perfect, Green Bay'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 Green Bay water systems is 0.0025 mg/L — within EPA limits. No ZIP codes exceed the EPA lead action level.
With 67% of homes built before 1986, Green Bay 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
Green Bay is in EPA Radon Zone 2 (Moderate risk). Testing is recommended, especially for homes with basements or ground-level living spaces.
Water Systems Serving Green Bay
Green Bay is served by 5 community water systems regulated under the Safe Drinking Water Act. These systems collectively serve approximately 177,103 people across 12 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 120 enforcement actions against water systems serving Green Bay. Enforcement actions range from informal compliance assistance to formal orders and penalties.
How to Check Your Water in Green Bay
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 Green Bay Water Systems
The following contaminants have been detected or caused violations across Green Bay's water systems:
| Contaminant | Category | MCL | Violations | ZIPs Affected | Health-Based |
|---|---|---|---|---|---|
| Haloacetic Acids (HAA5) | Disinfection Byproducts | 0.06 mg/L | 12 | 12 | No |
| Stage 2 DBP Rule | Treatment Technique | N/A | 12 | 12 | Yes |
| Lead and Copper Rule | Treatment Technique | N/A | 12 | 12 | No |
| Gross Beta | Radionuclides | 50 pCi/L | 12 | 12 | 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 Green Bay:
| Year | Total Violations | Health-Based |
|---|---|---|
| 2023 | 12 | 12 |
| 2024 | 24 | 24 |
Violations have increased from 12 in 2023 to 24 in 2024. This trend warrants monitoring.
EPA Enforcement History
The EPA and state regulators have taken 10 enforcement actions against water systems serving Green Bay. Recent actions:
| Date | Action Type |
|---|---|
| 2025-06-30 | State Informal Action |
| 2025-06-30 | State Order Extension |
| 2025-06-27 | State Informal Action |
| 2025-06-27 | State Order Extension |
| 2025-05-27 | State Order Extension |
| 2024-12-13 | State Order Extension |
| 2024-01-19 | State Informal Action |
| 2023-12-21 | State Informal Action |
| 2023-12-21 | State Informal Enforcement |
| 2023-12-19 | State Order Extension |
Enforcement actions range from informal compliance assistance to formal orders and penalties. The most recent action was on 2025-06-30.
Green Bay vs. Nearby Wisconsin Cities
How Green Bay's water quality compares to similar cities in Wisconsin:
| City | Grade | Violations | Systems | Population |
|---|---|---|---|---|
| Green Bay | B | 72 | 5 | 177,103 |
| Racine | B | 112 | 4 | 128,750 |
| Oneida | C | 0 | 1 | 107,369 |
| Kenosha | C | 145 | 5 | 99,743 |
Water Quality by ZIP Code in Green Bay
Water quality varies across Green Bay's ZIP codes. The table below shows the worst-scoring and best-scoring areas:
| ZIP Code | Score | Grade | Violations | Health-Based |
|---|---|---|---|---|
| 54301 | 71 | B | 6 | 2 |
| 54302 | 71 | B | 6 | 2 |
| 54303 | 71 | B | 6 | 2 |
| 54311 | 76 | B | 6 | 2 |
| 54313 | 76 | B | 6 | 2 |
| 54304 | 81 | B | 6 | 2 |
| 54305 | 81 | B | 6 | 2 |
| 54306 | 81 | B | 6 | 2 |
| 54307 | 81 | B | 6 | 2 |
| 54308 | 81 | B | 6 | 2 |
| 54344 | 81 | B | 6 | 2 |
| 54324 | 81 | B | 6 | 2 |
| 54308 | 81 | B | 6 | 2 |
| 54307 | 81 | B | 6 | 2 |
| 54306 | 81 | B | 6 | 2 |
Common Questions About Green Bay Water
These are the most common questions residents search for about water quality in Green Bay, Wisconsin:
Is Green Bay water hard or soft? Water hardness varies by source. Green Bay's 5 water systems use multiple sources. Check your ZIP code report for specific hardness data.
Can I drink Green Bay tap water? Green Bay's water receives a grade of B (78/100). There are 24 health-based violations — consider filtration.
What is the best water filter for Green Bay? A NSF/ANSI 53-certified filter for lead removal is a good general choice. See our Water Filter Matcher for personalized recommendations.
Green Bay vs. Wisconsin Average
Understanding how Green Bay 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 Green Bay.
ZIP Codes in Green Bay
Green Bay spans 12 ZIP codes. The ZIP with the lowest water quality score is 54301. 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.