Water Quality in Seattle, WA: 4 Violations - Grade N/A
15 water systems · 36 directly mapped ZIP records
Available EPA records report 4 violations across 36 directly mapped ZIP records with known counts for Seattle. This is compliance evidence, not a property-level tap-water verdict.
Data: EPA Safe Drinking Water Information System (SDWIS)
Water Quality by ZIP Code in Seattle
This table shows typed EPA water evidence only. Missing violation counts are displayed as N/A, not zero.
| ZIP Code | Violations | Health | |
|---|---|---|---|
| 98188 | 3 | 1 | View report → |
| 98198 | 3 | 1 | View report → |
| 98148 | 1 | 1 | View report → |
| 98168 | 1 | 0 | View report → |
| 98101 | 0 | 0 | View report → |
| 98102 | 0 | 0 | View report → |
| 98103 | 0 | 0 | View report → |
| 98104 | 0 | 0 | View report → |
| 98105 | 0 | 0 | View report → |
| 98106 | 0 | 0 | View report → |
| 98107 | 0 | 0 | View report → |
| 98108 | 0 | 0 | View report → |
| 98109 | 0 | 0 | View report → |
| 98112 | 0 | 0 | View report → |
| 98115 | 0 | 0 | View report → |
Water Quality Overview
Seattle, Washington has directly mapped EPA water-system data for 36 ZIP codes. This page reports typed compliance facts and does not relabel the multi-source Home Safety Score as a drinking-water grade.
The available EPA records report 4 violations, including 1 health-based violation across 36 directly mapped ZIP records with reported counts.
Lead Levels
The average 90th percentile lead level across Seattle water systems is 0.0017 mg/L - within EPA limits. No exceedances appear among the 36 ZIP records with known lead status.
With 63% of homes built before 1986, Seattle 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.
Water Systems Serving Seattle
Seattle is served by 15 community water systems regulated under the Safe Drinking Water Act. These systems collectively serve approximately 994,393 people across 62 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 9 enforcement actions against water systems serving Seattle. Enforcement actions range from informal compliance assistance to formal orders and penalties.
How to Check Your Water in Seattle
Enter your ZIP code on ZipCheckup to see your specific water system data, including contaminant levels and violation history
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 Seattle Water Systems
The following contaminants have been detected or caused violations across Seattle's water systems:
| Contaminant | Category | MCL | Violations | ZIPs Affected | Health-Based |
|---|---|---|---|---|---|
| Surface Water Treatment Rule | Treatment Technique | N/A | 5 | 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 5 enforcement actions against water systems serving Seattle. Recent actions:
| Date | Action Type |
|---|---|
| 2025-02-19 | State Order Extension |
| 2024-11-12 | State Order Extension |
| 2023-07-21 | State Order Extension |
| 2023-06-23 | State Informal Action |
| 2022-12-08 | State Order Extension |
Enforcement actions range from informal compliance assistance to formal orders and penalties. The most recent action was on 2025-02-19.
Seattle vs. Nearby Washington Cities
How Seattle's water quality compares to similar cities in Washington:
| City | Direct EPA ZIPs | Violations | Systems | Population |
|---|---|---|---|---|
| Seattle | 36 | 4 | 15 | 994,393 |
| Spokane | 16 | 49 | 22 | 389,529 |
| Tacoma | 21 | 13 | 15 | 364,667 |
| Vancouver | 11 | 9 | 6 | 356,538 |
Water Quality by ZIP Code in Seattle
EPA coverage and recorded violations can differ across Seattle's ZIP codes. Missing counts are shown as unavailable, not zero:
| ZIP Code | Violations | Health-Based |
|---|---|---|
| 98188 | 3 | 1 |
| 98198 | 3 | 1 |
| 98148 | 1 | 1 |
| 98168 | 1 | 0 |
| 98101 | 0 | 0 |
| 98102 | 0 | 0 |
| 98103 | 0 | 0 |
| 98104 | 0 | 0 |
| 98105 | 0 | 0 |
| 98106 | 0 | 0 |
| 98107 | 0 | 0 |
| 98108 | 0 | 0 |
| 98109 | 0 | 0 |
| 98112 | 0 | 0 |
| 98115 | 0 | 0 |
Common Questions About Seattle Water
These are the most common questions residents search for about water quality in Seattle, Washington:
Is Seattle water hard or soft? Water hardness varies by source. Seattle's 15 water systems use multiple sources. Check your ZIP code report for specific hardness data.
Can I drink Seattle tap water? City-level EPA records cannot determine safety at a specific tap. The measured subset contains 1 health-based violation; check the affected utility record and consider certified testing.
What is the best water filter for Seattle? A NSF/ANSI 53-certified filter for lead removal is a good general choice. See our Water Filter Matcher for personalized recommendations.
Seattle vs. Washington Average
Understanding how Seattle compares to the broader Washington 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 Seattle.
ZIP Codes in Seattle
Seattle spans 62 ZIP codes. EPA water-system coverage is available for 36 directly mapped ZIP codes. 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
Source reporting periods vary. See each cited source for its publication schedule.