Washington Water Quality Report: 1,630 Violations Across 726 ZIPs
978 water systems · 726 ZIP codes · 1,630 violations · Updated 2026-05-31
Data: EPA Safe Drinking Water Information System (SDWIS), EPA ECHO Last verified: 2026-05-31
City Water Quality Map: Washington
Each circle represents a city. Size indicates population, color indicates water quality grade. Tap a circle for details.
Violation Trend
EPA violations across all water systems in Washington.
Cities with Most Violations in Washington
| # | City | Grade | Violations | Systems | Population | |
|---|---|---|---|---|---|---|
| 1 | Tacoma | A | 76 | 5 | 566,031 | Details → |
| 2 | Everett | A | 64 | 5 | 280,878 | Details → |
| 3 | Seattle | A | 62 | 5 | 1,160,710 | Details → |
| 4 | Kennewick | C | 39 | 5 | 121,130 | Details → |
| 5 | Oak Harbor | C | 38 | 5 | 26,126 | Details → |
| 6 | Yakima | B | 35 | 5 | 161,805 | Details → |
| 7 | Curlew | D | 35 | 1 | 29 | Details → |
| 8 | Puyallup | A | 30 | 5 | 94,301 | Details → |
| 9 | Vancouver | C | 28 | 5 | 494,300 | Details → |
| 10 | Pasco | B | 26 | 5 | 118,601 | Details → |
Cities with Best Water Quality in Washington
| # | City | Grade | Score | Systems | Population |
|---|---|---|---|---|---|
| 1 | Manchester | A | 99/100 | 1 | 10,437 |
| 2 | Malaga | A | 99/100 | 2 | 3,128 |
| 3 | Anderson Island | A | 99/100 | 1 | 1,380 |
| 4 | Lakewood | A | 97/100 | 2 | 62,287 |
| 5 | Silverdale | A | 97/100 | 5 | 60,726 |
| 6 | Lacey | A | 95/100 | 5 | 119,607 |
| 7 | Steilacoom | A | 95/100 | 1 | 8,545 |
| 8 | Long Beach | A | 95/100 | 1 | 4,592 |
| 9 | Fox Island | A | 95/100 | 1 | 3,255 |
| 10 | Black Diamond | A | 95/100 | 5 | 3,120 |
Most Common Contaminants in Washington
| Contaminant | Category | Violations | ZIPs Affected | Health Risk |
|---|---|---|---|---|
| Surface Water Treatment Rule | Treatment Technique | 445 | 275 | No |
| Lead | Inorganic | 246 | 165 | Yes |
| Haloacetic Acids (HAA5) | Disinfection Byproducts | 165 | 111 | Yes |
| Total Trihalomethanes (TTHM) | Disinfection Byproducts | 133 | 85 | Yes |
| Stage 1 DBP Rule | Treatment Technique | 68 | 52 | Yes |
| Total Organic Carbon | Disinfection Byproducts | 54 | 31 | No |
| E. coli | Microbiological | 50 | 23 | Yes |
| Barium | Inorganic | 38 | 19 | Yes |
| Nickel | Inorganic | 32 | 8 | Yes |
| Contaminant 2440 | Other | 28 | 19 | No |
Water Quality Overview
Washington has 978 community water systems serving approximately 13,281,647 people across 726 ZIP codes. These systems have accumulated 1,630 EPA violations, including 121 health-based violations.
Health-based violations account for 7% of all violations in Washington. These violations indicate contaminant levels that may pose direct risks to human health, as opposed to monitoring or reporting failures.
Violation Breakdown
| Violation Type | Count | Percentage |
|---|---|---|
| Health-based | 121 | 7.4% |
| Monitoring/Reporting | 1,509 | 92.6% |
| Total | 1,630 | 100% |
Health-based violations indicate contaminant levels exceeding EPA Maximum Contaminant Levels (MCLs). Monitoring violations indicate failures to test or report — these do not necessarily mean unsafe water, but they mean the water was not properly verified.
Cities with Most Violations
The following cities in Washington have the highest number of EPA violations:
| Rank | City | Grade | Violations | Water Systems | Population |
|---|---|---|---|---|---|
| 1 | Tacoma | A | 76 | 5 | 566,031 |
| 2 | Everett | A | 64 | 5 | 280,878 |
| 3 | Seattle | A | 62 | 5 | 1,160,710 |
| 4 | Kennewick | C | 39 | 5 | 121,130 |
| 5 | Oak Harbor | C | 38 | 5 | 26,126 |
| 6 | Yakima | B | 35 | 5 | 161,805 |
| 7 | Curlew | D | 35 | 1 | 29 |
| 8 | Puyallup | A | 30 | 5 | 94,301 |
| 9 | Vancouver | C | 28 | 5 | 494,300 |
| 10 | Pasco | B | 26 | 5 | 118,601 |
Violation counts are cumulative across all water systems serving each city. Higher counts may reflect larger systems with more monitoring requirements, not necessarily worse water quality.
Cities with Best Water Quality
These Washington cities maintain Grade A water with zero violations:
| Rank | City | Grade | Score | Water Systems | Population |
|---|---|---|---|---|---|
| 1 | Manchester | A | 99/100 | 1 | 10,437 |
| 2 | Malaga | A | 99/100 | 2 | 3,128 |
| 3 | Anderson Island | A | 99/100 | 1 | 1,380 |
| 4 | Lakewood | A | 97/100 | 2 | 62,287 |
| 5 | Silverdale | A | 97/100 | 5 | 60,726 |
| 6 | Lacey | A | 95/100 | 5 | 119,607 |
| 7 | Steilacoom | A | 95/100 | 1 | 8,545 |
| 8 | Long Beach | A | 95/100 | 1 | 4,592 |
| 9 | Fox Island | A | 95/100 | 1 | 3,255 |
| 10 | Black Diamond | A | 95/100 | 5 | 3,120 |
Violation Trend Over Time
Year-by-year EPA violations recorded across all water systems in Washington:
| Year | Total Violations | Health-Based |
|---|---|---|
| 2021 | 32 | 32 |
| 2022 | 101 | 101 |
| 2023 | 73 | 73 |
| 2024 | 66 | 66 |
| 2025 | 67 | 67 |
Violations have increased from 32 in 2021 to 67 in 2025. This trend warrants monitoring and may reflect expanded testing requirements rather than worsening quality.
Most Common Contaminants
The following contaminants have caused the most violations across Washington water systems:
| Contaminant | Category | Violations | ZIPs Affected | Health-Based |
|---|---|---|---|---|
| Surface Water Treatment Rule | Treatment Technique | 445 | 275 | No |
| Lead | Inorganic | 246 | 165 | Yes |
| Haloacetic Acids (HAA5) | Disinfection Byproducts | 165 | 111 | Yes |
| Total Trihalomethanes (TTHM) | Disinfection Byproducts | 133 | 85 | Yes |
| Stage 1 DBP Rule | Treatment Technique | 68 | 52 | Yes |
| Total Organic Carbon | Disinfection Byproducts | 54 | 31 | No |
| E. coli | Microbiological | 50 | 23 | Yes |
| Barium | Inorganic | 38 | 19 | Yes |
| Nickel | Inorganic | 32 | 8 | Yes |
| Fecal Coliform | Microbiological | 4 | 2 | Yes |
How to Check Your Water in Washington
Enter your ZIP code on ZipCheckup for detailed water system data including contaminant levels, violation history, and safety scores
Request your CCR — every water utility must provide an annual Consumer Confidence Report
Get a home test — certified kits ($20-$50) or professional lab tests ($150-$400)
Consider filtration — NSF-certified filters can address specific contaminants found in your area
EPA Enforcement
The EPA and state regulators have taken 2,636 enforcement actions against water systems in Washington. Enforcement actions range from compliance assistance to formal orders and penalties.
Data Sources
- Water quality: EPA Safe Drinking Water Information System (SDWIS)
- Enforcement: EPA ECHO
Updated daily.
What are EPA violations?
Health-based violations mean a contaminant was detected above the EPA's Maximum Contaminant Level (MCL) — the legal limit designed to protect human health. Washington has 121 such violations across its water systems. Not all violations cause illness, but repeated exceedances increase risk, especially for children and immunocompromised individuals.
Understanding water quality grades
ZipCheckup grades water systems from A to F based on EPA violation history, contaminant levels, and system compliance. Grade A means few or no violations; Grade F indicates persistent or serious issues. Grades are calculated per ZIP code and aggregated at the city, county, and state level.
Wondering about your tap water?
Water quality varies by ZIP code. Enter yours to see contaminant data, violations, and filtration recommendations specific to your area.
Check Your ZIP Code Water Quality →Frequently Asked Questions
Is the tap water safe to drink in Washington?
Washington has 978 community water systems with 1,630 recorded EPA violations, including 121 health-based. Water quality varies by city and ZIP code — check your specific location for detailed results.
How many water violations does Washington have?
Washington has 1,630 total EPA violations across 726 ZIP codes. 121 are health-based violations that indicate contaminant levels potentially harmful to human health. The remainder are monitoring or reporting violations.
Which city in Washington has the worst water quality?
Tacoma, WA has the most EPA violations among major cities in Washington with 76 recorded violations. Check individual ZIP codes for the most accurate picture of your local water quality.
Which city in Washington has the best water quality?
Manchester, WA ranks among the best for water quality in Washington with a grade of A. Multiple cities in Washington maintain strong EPA compliance records.
What contaminants are found in Washington drinking water?
Washington water systems are monitored for over 90 EPA-regulated contaminants including lead, copper, nitrates, disinfection byproducts, and bacteria. The most common violations vary by region — check your ZIP code for contaminant-specific data.