Community Water System · PWS WA5340900
Sammamish Plateau Water & Sewer
Operator location Sammamish, Washington - UCMR5 detected 6 PFAS compounds (upper-third PFAS panel (> 4 compounds)) on this PWS; SDWIS lists 77 violations and 79,362 people served.
- 79,362
- People served (this PWS)
- 77
- EPA violations (this PWS)
- 5
- Health-based (this PWS)
- 6 PFAS
- UCMR5 (this PWS)
Sammamish Plateau Water & Sewer standing, high SDWIS violation third
UCMR5 detected 6 PFAS compounds - upper-third PFAS panel (> 4 compounds). Corpus terciles use 29,740 systems serving 500+ (the sitemap cohort). Health-based share 6% is middle-third health share (≤ 23%). UCMR5: upper-third PFAS panel (> 4 compounds). Population rank #658 of 29,740 among systems serving 500+.
The verdict
Sammamish Plateau Water & Sewer sits in the upper third of the sitemap cohort by violation count (77), so the tables below sample a dense compliance trail rather than a near-clean ledger. Population served is large (79,362; larger served population (> 3,309)), so household exposure scale sits behind the violation mix. Health-based share is 6% (middle-third health share (≤ 23%)). UCMR5 detected 6 PFAS compounds (upper-third PFAS panel (> 4 compounds)).
- #658 of 29,740
- Population · /systems
- #25 of 766
- Population · WA
- 77
- Total EPA violations on record
- 6%
- Health-based (MCL / treatment failure)
Population ordinals match the sitemap cohort (systems serving 500+, population_served DESC). See methodology · corpus placement.
6 PFAS "forever chemicals" detected in testing under EPA's UCMR5 monitoring program.
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 |
Violation Count vs. the National Corpus
Sammamish Plateau Water & Sewer has 77 recorded EPA violations, 67% of the 29,740 public water systems serving 500+ people nationwide carry fewer, and 32% carry more. 6% of this system's own violations are health-based (5 of 77), and it ranks #658 of 29,740 by population served among that same cohort.
EPA violations vs. the national water-system corpus
Public water systems serving 500+ people (EPA SDWIS)
77 Around the middle fewer violations than 32% of 29,740 water systems
the national water-system corpus, bucketed by value
Each bar is a band; taller bars hold more water systems. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count and share, and where it sits relative to this entry.
Source EPA SDWIS · 2026-05-15
PFAS Testing Results (UCMR5)
Results from EPA's Fifth Unregulated Contaminant Monitoring Rule. 24 of 464 samples detected PFAS.
| Contaminant | Date | Result | MRL | Status |
|---|---|---|---|---|
| NMeFOSAA | 8/7/2023 | <6.00 ppt | 6.00 ppt | Not Detected |
| 9Cl-PF3ONS | 8/7/2023 | <2.00 ppt | 2.00 ppt | Not Detected |
| ADONA | 8/7/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHpS | 8/7/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFPeS | 8/7/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| NFDHA | 8/7/2023 | <20.00 ppt | 20.00 ppt | Not Detected |
| PFEESA | 8/7/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFMBA | 8/7/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFPeA | 8/7/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFMPA | 8/7/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| 8:2 FTS | 8/7/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| 4:2 FTS | 8/7/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| 6:2 FTS | 8/7/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFBA | 8/7/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFUnA | 8/7/2023 | <2.00 ppt | 2.00 ppt | Not Detected |
| HFPO-DA | 8/7/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| NEtFOSAA | 8/7/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| 11Cl-PF3OUdS | 8/7/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFHxA | 8/7/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFDoA | 8/7/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFDA | 8/7/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFOA | 8/7/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFOS | 8/7/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFNA | 8/7/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFHxS | 8/7/2023 | 3.70 ppt | 3.00 ppt | Detected |
| PFHpA | 8/7/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFBS | 8/7/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFTA | 8/7/2023 | <8.00 ppt | 8.00 ppt | Not Detected |
| PFTrDA | 8/7/2023 | <7.00 ppt | 7.00 ppt | Not Detected |
| 11Cl-PF3OUdS | 6/26/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFBA | 6/26/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| HFPO-DA | 6/26/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| ADONA | 6/26/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| 9Cl-PF3ONS | 6/26/2023 | <2.00 ppt | 2.00 ppt | Not Detected |
| 6:2 FTS | 6/26/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFUnA | 6/26/2023 | <2.00 ppt | 2.00 ppt | Not Detected |
| PFHxA | 6/26/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFDoA | 6/26/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFDA | 6/26/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| 4:2 FTS | 6/26/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFOS | 6/26/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFNA | 6/26/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFOA | 6/26/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFHxS | 6/26/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHpA | 6/26/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFBS | 6/26/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFPeS | 6/26/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| 8:2 FTS | 6/26/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFHpS | 6/26/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| NFDHA | 6/26/2023 | <20.00 ppt | 20.00 ppt | Not Detected |
UCMR5 PFAS record for Sammamish Plateau Water & Sewer
Open EPA SDWIS federal reports for PWS WA5340900 to cross-check UCMR5 detections and violation codes; state primacy agencies enforce the Safe Drinking Water Act locally.
Sources: EPA SDWIS · Washington State Department of Health, Office of Drinking Water
Nationwide peers
77 violations · 79,362 served: nearest cross-state SDWIS matches.
Cross-state systems with comparable violation load
Nearest cross-state community systems (500+ served) by total SDWIS violations on record.
Cross-state systems with similar served population
Nearest cross-state systems by EPA SDWIS population_served (same 500+ sitemap gate).
What to do with Sammamish Plateau Water & Sewer
Use this system's EPA-reported record as a starting filter, not a final verdict.
- See how every tracked system in Washington compares on the same EPA violation measures. Washington systems
- Check whether PFAS was detected at this system under UCMR5 testing. PFAS guide
- Find and compare another public water system by name or PWSID. Search systems
EPA SDWIS and UCMR5 figures are informational only, not a substitute for a certified lab test of your own tap water.