Sammamish, WA 98075
1 water system • 79,362 residents
Moderate water quality - consider filtration
Score: 45/100
Graded on EPA violations, contaminants, severity, compliance, and enforcement history. See methodology.
Data updated June 2026 • Sources: EPA ECHO and EPA Envirofacts
38
Contaminants Detected
77
Violations on Record
5
Health-Based Violations
0
Recent Violations
Grade Breakdown
45 / 100 points
Recommended Water Filters
- ✓Reverse Osmosis or Ion Exchange Filter
- ✓Ultraviolet (UV) Purification
Consult a water quality specialist for personalized recommendations.
Sammamish vs WA & National Average
Detected Contaminants
38 contaminants detected across water systems serving this ZIP code
| Contaminant | Category |
|---|---|
| Atrazine | Agricultural |
| Nitrate | Agricultural |
| Simazine | Agricultural |
| Antimony, Total | Heavy Metal |
| Arsenic | Heavy Metal |
| Barium | Heavy Metal |
| Beryllium, Total | Heavy Metal |
| Cadmium | Heavy Metal |
| Chromium | Heavy Metal |
| Mercury | Heavy Metal |
| Nickel | Heavy Metal |
| Selenium | Heavy Metal |
| Thallium, Total | Heavy Metal |
| CYANIDE | Inorganic |
| Fluoride | Inorganic |
| Coliform (TCR) | Microorganism |
| 1,2-DIBROMO-3-CHLOROPROPANE | Other |
| 2,4,5-TP | Other |
| Benzo(a)pyrene | Other |
| BHC-GAMMA | Other |
| Chlordane | Other |
| Dalapon | Other |
| Di(2-ethylhexyl) adipate | Other |
| Di(2-ethylhexyl) phthalate | Other |
| Dinoseb | Other |
| Diquat | Other |
| Endrin | Other |
| ETHYLENE DIBROMIDE | Other |
| Heptachlor | Other |
| Heptachlor epoxide | Other |
| Hexachlorocyclopentadiene | Other |
| LASSO | Other |
| Methoxychlor | Other |
| Pentachlorophenol | Other |
| Picloram | Other |
| Toxaphene | Other |
| Gross Alpha, Excl. Radon and U | Radiological |
| HEXACHLOROBENZENE | Volatile Organic |
Water System Information
- Systems Serving This ZIP:
- SAMMAMISH PLATEAU WATER & SEWER
- Population Served:
- 79,362
- Systems With Violations:
- 1 of 1
- Major Violations:
- 66
- Enforcement Actions:
- 36
Frequently Asked Questions
What does the grade mean?
Our A–F grade ranks this ZIP code's water quality against every other analyzed ZIP in the country, based on EPA data. A = among the best, F = among the most troubled.
Is my tap water safe to drink?
Water systems regulated by the EPA must comply with Safe Drinking Water Act standards. However, if you're concerned about water quality, consider a water filter appropriate for your contaminants.
How often is the data updated?
We update our data quarterly with the latest EPA ECHO and Envirofacts data. Historical violations are tracked to identify patterns.
What filters do you recommend?
Filter recommendations are based on detected contaminants in your area. See our Filter Guide for detailed information about different filter types.