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Community Water System · PWS WA5390260

Union Hill Water Association Inc

Redmond, Washington 98053 - drinking water served from groundwater sources to 8,720 people, tracked in EPA SDWIS and UCMR5.

8,720
People served
312
EPA violations
3
Health-based
No PFAS
UCMR5 result

The verdict

EPA records 312 drinking-water violations at Union Hill Water Association Inc, 1% of them health-based - above the Washington per-system average.

312
Total EPA violations on record
1%
Health-based (MCL / treatment failure)
8,720
People served by this system
0
PFAS compounds detected (UCMR5)

Water Quality Snapshot: Union Hill Water Association Inc

Union Hill Water Association Inc is a private-owned community water system that delivers drinking water to 8,720 residents in Redmond, Washington (King County) through 2,104 service connections. Its water is drawn from groundwater sources. EPA's Safe Drinking Water Information System records 312 total violations for this system , of which 3 (1%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 306 monitoring and reporting violations are on file. The most recent violation on record dates to 2013.

The most frequently cited contaminant at this system is 1,2,4-Trichlorobenzene, recorded in 7 violations (MR). This system was sampled under EPA's UCMR5 PFAS monitoring program and no PFAS compounds were detected above the minimum reporting level.

Across Washington, EPA tracks 4,557 public water systems serving 9,736,844 people, with 314,648 cumulative violations and 20,590 health-based violations on record. About 92% of systems in the state carry at least one violation, and state-wide the average per system is 69 violations. Statewide, 98 of 247 UCMR5-tested systems have reported PFAS detections (39.7%).

Union Hill Water Association Inc's 312 violations sit above the Washington average.

All figures above are sourced directly from EPA SDWIS and UCMR5 public data releases and are updated as EPA publishes new reporting cycles.

Population Served
8,720
Total Violations
312
Health-Based Violations
3
Water Source
Groundwater

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

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

Verify This Water System

The figures above are aggregated from EPA's public databases. To verify the underlying records, or to file a complaint, request a Consumer Confidence Report, or check current monitoring status, go directly to the federal and state regulators that enforce the Safe Drinking Water Act for Union Hill Water Association Inc.

Federal Source of Truth

EPA SDWIS, Federal Reports

EPA's Safe Drinking Water Information System (SDWIS) holds the federal compliance record for every regulated public water system. Open the system-level report by PWS ID:

View PWS ID WA5390260 on SDWIS

Source: EPA SDWIS Federal Reports Search

State Regulator

Washington Drinking Water Authority

Washington State Department of Health, Office of Drinking Water is the primacy agency that licenses and inspects Union Hill Water Association Inc under EPA-delegated authority.

Open WA regulator portal

Source: Washington State Department of Health, Office of Drinking Water

Violation Timeline

Each row links to the EPA SDWIS public record for verification. Cross-reference the contaminant code on EPA's federal report to see violation dates, return-to-compliance status, and enforcement actions.

Year (latest) Contaminant Category Count EPA Record
2013 Consumer Confidence Rule Other 2 SDWIS / WA5390260 / 7000
2005 1,2,4-Trichlorobenzene MR 7 SDWIS / WA5390260 / 2378
2005 o-Dichlorobenzene MR 7 SDWIS / WA5390260 / 2968
2005 p-Dichlorobenzene MR 7 SDWIS / WA5390260 / 2969
2005 trans-1,2-Dichloroethylene MR 7 SDWIS / WA5390260 / 2979
2005 1,2-Dichloroethane MR 7 SDWIS / WA5390260 / 2980
2005 1,1,1-Trichloroethane MR 7 SDWIS / WA5390260 / 2981
2005 Carbon tetrachloride MR 7 SDWIS / WA5390260 / 2982
2005 1,2-Dichloropropane MR 7 SDWIS / WA5390260 / 2983
2005 Tetrachloroethylene MR 7 SDWIS / WA5390260 / 2987
2005 Benzene MR 7 SDWIS / WA5390260 / 2990
2005 Ethylbenzene MR 7 SDWIS / WA5390260 / 2992
2005 Styrene MR 7 SDWIS / WA5390260 / 2996
2005 DICHLOROMETHANE MR 7 SDWIS / WA5390260 / 2964
2005 Toluene MR 7 SDWIS / WA5390260 / 2991

How Union Hill Water Association Inc Compares

Cross-reference this system's record against state averages and the federal MCL framework for context.

Metric Union Hill Water Association Inc Washington avg Federal benchmark
Total violations 312 69 SDWA compliance, any non-zero count is a recorded breach
Health-based violations 3 4.5 Indicates a contaminant exceeded a federal MCL
PFAS detection None 39.7% EPA final rule (2024): PFOA/PFOS MCL = 4.0 ppt
Population served 8,720 2,137 Sizing context for compliance burden

Sources: EPA SDWIS and EPA National Primary Drinking Water Regulations (40 CFR Part 141). State averages computed across 4,557 regulated public water systems in Washington.

Federal MCL reference, Safe Drinking Water Act thresholds ▼
Contaminant Federal MCL / Action Level Note
Lead 0 mg/L (Action Level: 0.015 mg/L) Lead and Copper Rule treatment technique
Arsenic 0.010 mg/L (10 ppb) Health-based MCL since 2006
Total Coliform Treatment technique (RTCR) Indicator organism, monitoring trigger
PFOA / PFOS (PFAS) 4.0 ppt each (final 2024 rule) Compliance deadline 2029 (EPA proposed extending to 2031, not yet final as of May 2026)
Nitrate (as N) 10 mg/L Acute health risk for infants

Frequently Asked Questions

Is Union Hill Water Association Inc water safe to drink? ▼
Union Hill Water Association Inc (PWS ID: WA5390260) has 312 recorded violations in the EPA SDWIS database. No PFAS contamination was detected in UCMR5 testing. This system serves 8,720 people using Groundwater sources.
How many people does Union Hill Water Association Inc serve? ▼
Union Hill Water Association Inc serves 8,720 people in Redmond, Washington. It is a Private-owned system using Groundwater water sources with 2,104 service connections.
What type of violations does Union Hill Water Association Inc have? ▼
Union Hill Water Association Inc has 312 total violations: 3 health-based violations (MCL exceedances or treatment failures), 306 monitoring/reporting violations, and 0 treatment technique violations. Health-based violations indicate contaminant levels exceeded EPA safe limits.
Has PFAS been detected in Union Hill Water Association Inc water? ▼
No. Union Hill Water Association Inc was tested for PFAS under the EPA's UCMR5 monitoring program and no PFAS contamination was detected.
What water source does Union Hill Water Association Inc use? ▼
Union Hill Water Association Inc uses Groundwater as its primary water source. It is classified as a Community Water System (CWS), serving residential populations year-round.
Where does this data come from? ▼
All data comes from the EPA Safe Drinking Water Information System (SDWIS) and the UCMR5 PFAS monitoring program. SDWIS tracks compliance for all public water systems regulated under the Safe Drinking Water Act.
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.

Read our methodology - how this data is sourced, computed, and verified.

Data sourced from EPA SDWIS and UCMR5 PFAS monitoring data. See our methodology for details. Retrieved and formatted by PlainWater Editorial

Every figure on PlainWater is rendered directly from EPA SDWIS drinking-water data, no number is typed in by an editor. This system's figures are rendered directly from EPA SDWIS data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.