Public water system · WA5331565
ActiveHarstine Island Estates Assn
At a glance
Harstine Island Estates Assn (PWSID WA5331565) is an active community water system in Mason County, Washington. It reports serving 56 people through 62 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 October 2023.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
56
Service connections
62
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Harstine Island Estates Assn compare with other water systems in Mason County?
By EPA's size categories, Harstine Island Estates Assn is a very small system (500 people or fewer). Mason County has 240 active public water systems. Its population served is well below the county average of 315 people per system, and accounts for less than 0.1% of the 75,633 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 Harstine Island Estates Assn 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 Harstine Island Estates Assn?
EPA lists Harstine Island Estates Assn 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. 163 of the 240 active systems in Mason County (68%) are also privately owned.
Does Harstine Island Estates Assn have drinking water violations?
Of the 12 most recent violations in EPA's records, none is health-based, and the most recent began in October 2023. The violations listed here began between January 2008 and October 2023. By type: 10 monitoring and reporting and 2 monitoring. The contaminant or rule involved most often is Revised Total Coliform Rule (2 of them). EPA lists 12 as resolved. Resolved means at least one resolving action is on record: the system returned to compliance, the rule no longer applies, or no further action was needed.
| Began | Violation | Contaminant or rule | Health-based | Status |
|---|---|---|---|---|
| 2023-10-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2022-07-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2020-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | No | Resolved |
| 2008-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Toxaphenecode 2020 | No | Resolved |
| 2008-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Pentachlorophenolcode 2326 | No | Resolved |
| 2008-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Hexachlorocyclopentadienecode 2042 | No | Resolved |
| 2008-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | 2,4,5-TP (Silvex)code 2110 | No | Resolved |
| 2008-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Heptachlor epoxidecode 2067 | No | Resolved |
| 2008-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Hexachlorobenzenecode 2274 | No | Resolved |
| 2008-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Benzo(a)pyrenecode 2306 | No | Resolved |
| 2008-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Heptachlorcode 2065 | No | Resolved |
| 2008-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Dinosebcode 2041 | No | Resolved |
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.
Harstine Island Estates Assn: frequently asked questions
Who runs Harstine Island Estates Assn?
Harstine Island Estates Assn (PWSID WA5331565) is a community water system privately owned. It is regulated by the WA state drinking water program.
How many people does Harstine Island Estates Assn serve?
Harstine Island Estates Assn reports serving 56 people through 62 service connections in Mason County, Washington.
Where does Harstine Island Estates Assn 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 Harstine Island Estates Assn 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 October 2023. 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 Harstine Island Estates Assn'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 October 2023. For current results, consult the system's annual water quality report, EPA ECHO, or the WA state drinking water program.
Where can I find Harstine Island Estates Assn's water quality report?
As a community water system, Harstine Island Estates Assn 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 Mason County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Shelton City of | Mason | 15,089 | Community | Groundwater |
| Belfair Water District 1 | Mason | 4,432 | Community | Groundwater |
| Lake Cushman System 5 | Mason | 3,675 | Community | Groundwater |
| Twanoh State Park | Mason | 3,173 | Transient non-community | Groundwater |
| Belfair State Park | Mason | 2,411 | Transient non-community | Groundwater |
| Timberlake Community Club Inc. | Mason | 2,337 | 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, “Harstine Island Estates Assn, PWSID WA5331565, Washington”, https://aquacensus.com/water-systems/washington/harstine-island-estates-assn-wa5331565 (data as of October 1, 2026).