Public water system · WA5389150
ActiveTreasure Island Country Club
At a glance
Treasure Island Country Club (PWSID WA5389150) is an active community water system in Mason County, Washington. It reports serving 321 people through 240 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, 8 are health-based, and the most recent began in July 2022.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
321
Service connections
240
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Treasure Island Country Club compare with other water systems in Mason County?
By EPA's size categories, Treasure Island Country Club is a very small system (500 people or fewer). Mason County has 240 active public water systems. Its population served is roughly in line with the county average of 315 people per system, and accounts for 0.4% 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 Treasure Island Country Club 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 Treasure Island Country Club?
EPA lists Treasure Island Country Club 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 Treasure Island Country Club have drinking water violations?
Of the 12 most recent violations in EPA's records, 8 are health-based, and the most recent began in July 2022. The violations listed here began between July 1992 and July 2022. By type: 8 contaminant level above the legal limit, 3 monitoring and reporting and 1 monitoring. The contaminant or rule involved most often is Total coliform bacteria (TCR) (10 of them). EPA lists 10 as archived and 2 as resolved. 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. 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 |
|---|---|---|---|---|
| 2022-07-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2006-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Archived |
| 2006-09-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Archived |
| 2005-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Diquatcode 2032 | No | Resolved |
| 1995-12-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Acute (TCR) · code 21 | Total coliform bacteria (TCR)code 3100 | Yes | Archived |
| 1994-09-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Archived |
| 1993-09-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Archived |
| 1993-08-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Archived |
| 1993-03-01 | Monitoring and reportingMonitoring, Repeat Major (TCR) · code 25 | Total coliform bacteria (TCR)code 3100 | No | Archived |
| 1992-12-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Archived |
| 1992-08-01 | Monitoring and reportingMonitoring, Routine Minor (TCR) · code 24 | Total coliform bacteria (TCR)code 3100 | No | Archived |
| 1992-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Acute (TCR) · code 21 | Total coliform bacteria (TCR)code 3100 | Yes | 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.
Treasure Island Country Club: frequently asked questions
Who runs Treasure Island Country Club?
Treasure Island Country Club (PWSID WA5389150) is a community water system privately owned. It is regulated by the WA state drinking water program.
How many people does Treasure Island Country Club serve?
Treasure Island Country Club reports serving 321 people through 240 service connections in Mason County, Washington.
Where does Treasure Island Country Club 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 Treasure Island Country Club have any drinking water violations?
Of the 12 most recent violations in EPA's records, 8 are health-based, and the most recent began in July 2022. 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 Treasure Island Country Club'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, 8 are health-based, and the most recent began in July 2022. For current results, consult the system's annual water quality report, EPA ECHO, or the WA state drinking water program.
Where can I find Treasure Island Country Club's water quality report?
As a community water system, Treasure Island Country Club 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, “Treasure Island Country Club, PWSID WA5389150, Washington”, https://aquacensus.com/water-systems/washington/treasure-island-country-club-wa5389150 (data as of October 1, 2026).