Public water system · WA5378970
ActiveSierra Vista Water Association
At a glance
Sierra Vista Water Association (PWSID WA5378970) is an active community water system in Island County, Washington. It reports serving 197 people through 84 service connections. Its primary water source is groundwater, and EPA lists it as privately owned. Of the 12 most recent violations in EPA's records, none is health-based, and the most recent began in January 2025.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
197
Service connections
84
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Sierra Vista Water Association compare with other water systems in Island County?
By EPA's size categories, Sierra Vista Water Association is a very small system (500 people or fewer). Island County has 307 active public water systems. Its population served is about 41% below the county average of 335 people per system, and accounts for 0.2% of the 102,977 people reported by systems filed under the county. Across Washington, the 4,705 active systems average 2,172 people each. Nationally, the average active community water system reports serving 6,703 people, so Sierra Vista Water Association is well below that figure.
What does “community water system” mean?
A community water system serves at least 15 connections used by year-round residents, or regularly serves at least 25 year-round residents. Homes, apartments and mobile-home parks are served by these. Washington has 2,392 active community water systems, 51% of the state's 4,705 active systems. Groundwater means the system draws its water from wells or springs fed by underground aquifers. 4,370 Washington systems (93%) list groundwater as their primary source.
Who owns and regulates Sierra Vista Water Association?
EPA lists Sierra Vista Water Association as privately owned. The WA state drinking water program is its primacy agency, the regulator with primary enforcement responsibility for the system under the Safe Drinking Water Act. 274 of the 307 active systems in Island County (89%) are also privately owned.
Does Sierra Vista Water Association have drinking water violations?
Of the 12 most recent violations in EPA's records, none is health-based, and the most recent began in January 2025. The violations listed here began between January 2023 and January 2025. By type: 12 monitoring and reporting. The contaminants or rules involved are Nitrate, 1,1,1-Trichloroethane, Trichloroethylene and 1,2-Dichloropropane. EPA lists 12 as archived. Archived means the violation was not marked resolved but is more than five years past the end of the noncompliance period, so it no longer counts toward current compliance status.
| Began | Violation | Contaminant or rule | Health-based | Status |
|---|---|---|---|---|
| 2025-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | No | Archived |
| 2023-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | 1,1,1-Trichloroethanecode 2981 | No | Archived |
| 2023-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Trichloroethylenecode 2984 | No | Archived |
| 2023-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | 1,2-Dichloropropanecode 2983 | No | Archived |
| 2023-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | trans-1,2-Dichloroethylenecode 2979 | No | Archived |
| 2023-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Carbon tetrachloridecode 2982 | No | Archived |
| 2023-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Vinyl chloridecode 2976 | No | Archived |
| 2023-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Chlorobenzenecode 2989 | No | Archived |
| 2023-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | 1,2-Dichloroethanecode 2980 | No | Archived |
| 2023-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | 1,1-Dichloroethylenecode 2977 | No | Archived |
| 2023-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Ethylbenzenecode 2992 | No | Archived |
| 2023-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | 1,1,2-Trichloroethanecode 2985 | No | Archived |
The 12 most recent violations in EPA's records, newest first.Labels and codes come from EPA's SDWIS reference tables. A monitoring or reporting violation means a required test or report was missed or late; it does not by itself mean a contaminant was found. "Health-based" marks violations of a legal limit or required treatment.
Sierra Vista Water Association: frequently asked questions
Who runs Sierra Vista Water Association?
Sierra Vista Water Association (PWSID WA5378970) is a community water system privately owned. It is regulated by the WA state drinking water program.
How many people does Sierra Vista Water Association serve?
Sierra Vista Water Association reports serving 197 people through 84 service connections in Island County, Washington.
Where does Sierra Vista Water Association get its water?
EPA SDWIS lists this system's primary water source as groundwater. Groundwater means the system draws its water from wells or springs fed by underground aquifers.
Does Sierra Vista Water Association have any drinking water violations?
Of the 12 most recent violations in EPA's records, none is health-based, and the most recent began in January 2025. A monitoring or reporting violation means a required test or report was missed or late; it does not by itself mean a contaminant was found.
Is Sierra Vista Water Association's water safe to drink?
AquaCensus shows EPA compliance records, not current water test results, so it cannot say whether the water is safe at a given moment. Of the 12 most recent violations in EPA's records, none is health-based, and the most recent began in January 2025. For current results, consult the system's annual water quality report, EPA ECHO, or the WA state drinking water program.
Where can I find Sierra Vista Water Association's water quality report?
As a community water system, Sierra Vista Water Association must deliver an annual water quality report, called a Consumer Confidence Report, to its customers by July 1 each year, covering the previous calendar year. The system can provide a copy on request.
Other water systems in Island County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Oak Harbor City of | Island | 23,675 | Community | Purchased surface water |
| Naval Air Station/Whidbey Island | Island | 16,595 | Community | Purchased surface water |
| Coupeville Town of | Island | 4,142 | Community | Groundwater |
| Camano Water Association | Island | 2,592 | Community | Groundwater |
| Clinton Water District | Island | 1,980 | Community | Groundwater |
| Camano Island State Park | Island | 1,718 | Transient non-community | Groundwater |
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About this data
Source: U.S. EPA Safe Drinking Water Information System (SDWIS) and SDWA violation records, via EPA ECHO, as published October 1, 2026 — AquaCensus refreshes it quarterly. See the methodology for how records are matched, cleaned and scored.
Cite as: AquaCensus, “Sierra Vista Water Association, PWSID WA5378970, Washington”, https://aquacensus.com/water-systems/washington/sierra-vista-water-association-wa5378970 (data as of October 1, 2026).