Mason County Water Quality: 187 Violations (WA)
12 water systems · 7 ZIP codes · Home Safety Score 98/100 (A) · 3 of 10 tracked ZIP records scored · Updated
Data: EPA Safe Drinking Water Information System (SDWIS), EPA ECHO Last verified:
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Find the Right Filter →Water Quality Overview
Mason County has 12 community water systems across 7 directly mapped ZIP records. The systems report serving approximately 35,067 people. The available records contain 187 EPA violations, including 1 health-based violation.
Health-based violations account for 1% of all violations in Mason County. These violations indicate contaminant levels that may pose direct risks to human health.
Violation Breakdown
| Violation Type | Count | Percentage |
|---|---|---|
| Health-based | 1 | 0.5% |
| Monitoring/Reporting | 186 | 99.5% |
| Total | 187 | 100% |
Health-based violations indicate contaminant levels exceeding EPA Maximum Contaminant Levels (MCLs). Monitoring violations indicate failures to test or report.
Cities with Most Violations
| Rank | City | Violations | Health-Based | ZIP Codes | Population |
|---|---|---|---|---|---|
| 1 | Belfair | 166 | 1 | 1 | 12,398 |
| 2 | Grapeview | 6 | 0 | 1 | 2,288 |
| 3 | Shelton | 5 | 0 | 1 | 40,036 |
| 4 | Union | 4 | 0 | 1 | 1,666 |
| 5 | Allyn | 2 | 0 | 1 | 4,585 |
| 6 | Hoodsport | 2 | 0 | 1 | 2,336 |
| 7 | Lilliwaup | 2 | 0 | 1 | 213 |
Most Common Contaminants
| Contaminant | Category | Violations | ZIPs Affected | Health-Based |
|---|---|---|---|---|
| Surface Water Treatment Rule | Treatment Technique | 11 | 4 | No |
| PFOA | PFAS | 5 | 1 | No |
| PFNA | PFAS | 5 | 1 | No |
| Dichloroacetic Acid | Disinfection Byproducts | 5 | 1 | No |
| Bromodichloromethane | Disinfection Byproducts | 5 | 1 | No |
| Dibromochloromethane | Disinfection Byproducts | 5 | 1 | No |
| Bromoform | Disinfection Byproducts | 5 | 1 | No |
| Chlorodibromomethane | Disinfection Byproducts | 5 | 1 | No |
| Trichloroacetic Acid | Disinfection Byproducts | 5 | 1 | No |
| Monobromoacetic Acid | Disinfection Byproducts | 5 | 1 | No |
Water Data and the Home Safety Score
This page reports EPA water-system facts without converting the broader Home Safety Score into a drinking-water grade. The county Home Safety grade (A) is a separate multi-source index that also requires PFAS screening, radon, and annual air-quality evidence. Check each ZIP report for the versioned score and its component coverage.
Water Systems in Mason County
Mason County is served by 12 community water systems, averaging 1.2 systems per ZIP code. Each system is independently regulated and tested by the EPA. Larger systems serving more people typically have more extensive monitoring requirements.
Water systems in Mason County source water from a mix of surface water (rivers, reservoirs) and groundwater (wells, aquifers). Source type affects which contaminants are most likely to be detected.
How to Check Your Water in Mason County
Enter your ZIP code on ZipCheckup for detailed water-system data including contaminant levels and violation history; the Home Safety Score is shown separately with its model version
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) can detect contaminants not covered by routine testing
Consider filtration — NSF-certified filters can address specific contaminants found in your area
Check for lead — homes built before 1986 should test for lead regardless of utility compliance
EPA Enforcement
The EPA and state regulators have taken 25 enforcement actions against water systems in Mason County. Enforcement actions range from compliance assistance and administrative orders to formal penalties. Systems under enforcement are required to remediate violations and may face ongoing monitoring requirements.
Data Sources
- Water quality: EPA Safe Drinking Water Information System (SDWIS)
- Enforcement: EPA ECHO
Source publication schedules vary. See the page source and verification fields for available timing evidence.
Water Quality by ZIP Code in Mason County
Water quality varies across Mason County's 7 ZIP codes. Check your specific ZIP for detailed contaminant data.
Water facts and the Home Safety Score
The score shown here is the broader Home Safety Score, not a water-quality grade. Model 4.0.0 combines EPA SDWIS identity plus accepted ECHO SDWA lifecycle-based water compliance, PFAS screening, radon zones, and annual air-quality evidence. Mason County has a score of 98/100 (Grade A) across 3 scored of 10 tracked ZIP records.
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Find the Right Filter →Frequently Asked Questions
Is the tap water safe in Mason County, Washington?
Mason County has 12 community water systems with 187 recorded EPA violations, including 1 health-based. Water quality varies by ZIP code - check your specific location for detailed results.
How many water violations does Mason County have?
Mason County has 187 total EPA violations across 7 directly mapped ZIP records. 1 is health-based.
Which city in Mason County has the most water violations?
Belfair has the most violations in Mason County with 166 recorded EPA violations across 1 ZIP code.
What contaminants are found in Mason County water?
Mason County water systems are monitored for over 90 EPA-regulated contaminants including lead, copper, nitrates, disinfection byproducts, and bacteria. Check your ZIP code for contaminant-specific data.
How can I test my water in Mason County?
Contact your local water utility for free or low-cost testing. You can also use a certified home test kit ($20-$50) or hire a certified lab ($150-$400).