Community Water System · PWS WA5390260
Union Hill Water Association Inc
Operator location Redmond, Washington - larger served population (> 3,309) at 8,720 people served; 312 SDWIS violations on record from groundwater sources.
- 8,720
- People served (this PWS)
- 312
- EPA violations (this PWS)
- 3
- Health-based (this PWS)
- No PFAS
- UCMR5 (this PWS)
Union Hill Water Association Inc standing, high SDWIS violation third
8,720 people served (SDWIS) - larger served population (> 3,309). Corpus terciles use 29,740 systems serving 500+ (the sitemap cohort). Health-based share 1% is middle-third health share (≤ 23%). UCMR5: UCMR5 tested, none detected. Population rank #5,253 of 29,740 among systems serving 500+.
The verdict
Union Hill Water Association Inc sits in the upper third of the sitemap cohort by violation count (312), so the tables below sample a dense compliance trail rather than a near-clean ledger. Population served is large (8,720; larger served population (> 3,309)), so household exposure scale sits behind the violation mix. Health-based share is 1% (middle-third health share (≤ 23%)). UCMR5 tested this system and reported no PFAS above the minimum reporting level.
- #5,253 of 29,740
- Population · /systems
- #145 of 766
- Population · WA
- 312
- Total EPA violations on record
- 1%
- Health-based (MCL / treatment failure)
Population ordinals match the sitemap cohort (systems serving 500+, population_served DESC). See methodology · corpus placement.
System Details
- System Type
- Community
- Owner Type
- Private
- Connections
- 2,104
- County
- King
- School/Daycare
- No
- MCL Violations
- 3
- Monitoring Violations
- 306
- Treatment Tech Violations
- 0
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| 1,2,4-Trichlorobenzene | MR | 7 | 2005 |
| o-Dichlorobenzene | MR | 7 | 2005 |
| p-Dichlorobenzene | MR | 7 | 2005 |
| trans-1,2-Dichloroethylene | MR | 7 | 2005 |
| 1,2-Dichloroethane | MR | 7 | 2005 |
| 1,1,1-Trichloroethane | MR | 7 | 2005 |
| Carbon tetrachloride | MR | 7 | 2005 |
| 1,2-Dichloropropane | MR | 7 | 2005 |
| Tetrachloroethylene | MR | 7 | 2005 |
| Benzene | MR | 7 | 2005 |
| Ethylbenzene | MR | 7 | 2005 |
| Styrene | MR | 7 | 2005 |
| DICHLOROMETHANE | MR | 7 | 2005 |
| Toluene | MR | 7 | 2005 |
| Vinyl chloride | MR | 7 | 2005 |
| Trichloroethylene | MR | 7 | 2005 |
| 1,1-Dichloroethylene | MR | 7 | 2005 |
| cis-1,2-Dichloroethylene | MR | 7 | 2005 |
| CHLOROBENZENE | MR | 7 | 2005 |
| Pentachlorophenol | MR | 7 | 2005 |
| 1,1,2-Trichloroethane | MR | 7 | 2005 |
| Methoxychlor | MR | 6 | 2005 |
| Toxaphene | MR | 6 | 2005 |
| Hexachlorocyclopentadiene | MR | 6 | 2005 |
| Atrazine | MR | 6 | 2005 |
| LASSO | MR | 6 | 2005 |
| Heptachlor | MR | 6 | 2005 |
| Heptachlor epoxide | MR | 6 | 2005 |
| HEXACHLOROBENZENE | MR | 6 | 2005 |
| Benzo(a)pyrene | MR | 6 | 2005 |
Violation Count vs. the National Corpus
Union Hill Water Association Inc has 312 recorded EPA violations, 91% of the 29,740 public water systems serving 500+ people nationwide carry fewer, and 9% carry more. 1% of this system's own violations are health-based (3 of 312), and it ranks #5,253 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)
312 Higher than most more violations than 91% 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. 0 of 58 samples detected PFAS.
| Contaminant | Date | Result | MRL | Status |
|---|---|---|---|---|
| PFTA | 3/21/2023 | <8.00 ppt | 8.00 ppt | Not Detected |
| PFBS | 3/21/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| NEtFOSAA | 3/21/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFNA | 3/21/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFTrDA | 3/21/2023 | <7.00 ppt | 7.00 ppt | Not Detected |
| NFDHA | 3/21/2023 | <20.00 ppt | 20.00 ppt | Not Detected |
| PFPeS | 3/21/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFHpS | 3/21/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHpA | 3/21/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHxS | 3/21/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFBA | 3/21/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFMBA | 3/21/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFEESA | 3/21/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFMPA | 3/21/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| 8:2 FTS | 3/21/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| NMeFOSAA | 3/21/2023 | <6.00 ppt | 6.00 ppt | Not Detected |
| 6:2 FTS | 3/21/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFPeA | 3/21/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| HFPO-DA | 3/21/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| 9Cl-PF3ONS | 3/21/2023 | <2.00 ppt | 2.00 ppt | Not Detected |
| 11Cl-PF3OUdS | 3/21/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFUnA | 3/21/2023 | <2.00 ppt | 2.00 ppt | Not Detected |
| PFHxA | 3/21/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFDoA | 3/21/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFDA | 3/21/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| ADONA | 3/21/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFOS | 3/21/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| 4:2 FTS | 3/21/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFOA | 3/21/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| 9Cl-PF3ONS | 10/10/2023 | <2.00 ppt | 2.00 ppt | Not Detected |
| 4:2 FTS | 10/10/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| 6:2 FTS | 10/10/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFBA | 10/10/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| ADONA | 10/10/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| HFPO-DA | 10/10/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| 8:2 FTS | 10/10/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFMPA | 10/10/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFPeA | 10/10/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFMBA | 10/10/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFEESA | 10/10/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| 11Cl-PF3OUdS | 10/10/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFPeS | 10/10/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| NFDHA | 10/10/2023 | <20.00 ppt | 20.00 ppt | Not Detected |
| PFDoA | 10/10/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHpS | 10/10/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFTA | 10/10/2023 | <8.00 ppt | 8.00 ppt | Not Detected |
| PFTrDA | 10/10/2023 | <7.00 ppt | 7.00 ppt | Not Detected |
| NEtFOSAA | 10/10/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| NMeFOSAA | 10/10/2023 | <6.00 ppt | 6.00 ppt | Not Detected |
| PFDA | 10/10/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
Population served record for Union Hill Water Association Inc
EPA SDWIS lists 8,720 people served and 2,104 connections for this PWS, confirm the service-area footprint on the federal report before comparing to municipal census totals.
Sources: EPA SDWIS · Washington State Department of Health, Office of Drinking Water
Nationwide peers
312 violations · 8,720 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 Union Hill Water Association Inc
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.