SAMMAMISH PLATEAU WATER & SEWER
PWS ID: WA5340900 · Sammamish, Washington 98075
PFAS Detected
6 PFAS "forever chemicals" detected in testing under EPA's UCMR5 monitoring program.
Population Served
79,362
Total Violations
77
Health-Based Violations
5
Water Source
Surface Water
System Details
- System Type
- Community
- Owner Type
- Local
- Connections
- 24,792
- County
- King
- School/Daycare
- No
- MCL Violations
- 5
- Monitoring Violations
- 71
- Treatment Tech Violations
- 0
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| Diquat | MR | 10 | 2008 |
| ETHYLENE DIBROMIDE | MR | 10 | 2008 |
| 1,2-DIBROMO-3-CHLOROPROPANE | MR | 10 | 2008 |
| Coliform (TCR) | MR | 5 | 1995 |
| Coliform (TCR) | MCL | 5 | 2004 |
| Nitrate | MR | 2 | 2009 |
| Pentachlorophenol | MR | 2 | 2008 |
| Barium | MR | 1 | 2005 |
| Mercury | MR | 1 | 2005 |
| Dalapon | MR | 1 | 2008 |
| Fluoride | MR | 1 | 2005 |
| Chlordane | MR | 1 | 2008 |
| Beryllium, Total | MR | 1 | 2005 |
| Hexachlorocyclopentadiene | MR | 1 | 2008 |
| LASSO | MR | 1 | 2008 |
| Cadmium | MR | 1 | 2005 |
| Picloram | MR | 1 | 2008 |
| Methoxychlor | MR | 1 | 2008 |
| Benzo(a)pyrene | MR | 1 | 2008 |
| Heptachlor epoxide | MR | 1 | 2008 |
| CYANIDE | MR | 1 | 2005 |
| Atrazine | MR | 1 | 2008 |
| Di(2-ethylhexyl) phthalate | MR | 1 | 2008 |
| Di(2-ethylhexyl) adipate | MR | 1 | 2008 |
| Endrin | MR | 1 | 2008 |
| BHC-GAMMA | MR | 1 | 2008 |
| Antimony, Total | MR | 1 | 2005 |
| Dinoseb | MR | 1 | 2008 |
| Gross Alpha, Excl. Radon and U | MR | 1 | 1979 |
| Heptachlor | MR | 1 | 2008 |
PFAS Testing Results (UCMR5)
Results from EPA's Fifth Unregulated Contaminant Monitoring Rule. 24 of 480 samples detected PFAS.
| Contaminant | Date | Result | MRL | Status |
|---|---|---|---|---|
| NMeFOSAA | 8/7/2023 | <0.006 µg/L | 0.006 µg/L | Not Detected |
| 9Cl-PF3ONS | 8/7/2023 | <0.002 µg/L | 0.002 µg/L | Not Detected |
| lithium | 8/7/2023 | <9 µg/L | 9 µg/L | Not Detected |
| ADONA | 8/7/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFHpS | 8/7/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFPeS | 8/7/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| NFDHA | 8/7/2023 | <0.02 µg/L | 0.02 µg/L | Not Detected |
| PFEESA | 8/7/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFMBA | 8/7/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFPeA | 8/7/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFMPA | 8/7/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| 8:2 FTS | 8/7/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| 4:2 FTS | 8/7/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| 6:2 FTS | 8/7/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFBA | 8/7/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFUnA | 8/7/2023 | <0.002 µg/L | 0.002 µg/L | Not Detected |
| HFPO-DA | 8/7/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| NEtFOSAA | 8/7/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| 11Cl-PF3OUdS | 8/7/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFHxA | 8/7/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFDoA | 8/7/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFDA | 8/7/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFOA | 8/7/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFOS | 8/7/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFNA | 8/7/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFHxS | 8/7/2023 | 0.0037 µg/L | 0.003 µg/L | Detected |
| PFHpA | 8/7/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFBS | 8/7/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFTA | 8/7/2023 | <0.008 µg/L | 0.008 µg/L | Not Detected |
| PFTrDA | 8/7/2023 | <0.007 µg/L | 0.007 µg/L | Not Detected |
| 11Cl-PF3OUdS | 6/26/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFBA | 6/26/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| HFPO-DA | 6/26/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| ADONA | 6/26/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| 9Cl-PF3ONS | 6/26/2023 | <0.002 µg/L | 0.002 µg/L | Not Detected |
| 6:2 FTS | 6/26/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFUnA | 6/26/2023 | <0.002 µg/L | 0.002 µg/L | Not Detected |
| PFHxA | 6/26/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFDoA | 6/26/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFDA | 6/26/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| 4:2 FTS | 6/26/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFOS | 6/26/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFNA | 6/26/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFOA | 6/26/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFHxS | 6/26/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFHpA | 6/26/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFBS | 6/26/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFPeS | 6/26/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| 8:2 FTS | 6/26/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFHpS | 6/26/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
Data Sources: EPA Safe Drinking Water Information System (SDWIS), Q4 2025.
PFAS data from EPA UCMR5 monitoring program (2023-2025).
This data is provided for informational purposes only.