Public water system · WA5300620
ActivePort of Shelton Johns Prairie
At a glance
Port of Shelton Johns Prairie (PWSID WA5300620) is an active non-transient non-community water system in Mason County, Washington. It reports serving 328 people through 14 service connections. Its primary water source is purchased groundwater, and EPA lists it as owned by a local government. Of the 12 most recent violations in EPA's records, 2 are health-based, and the most recent began in April 2000.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
328
Service connections
14
Primary source
GWP
Purchased groundwater
System type
NTNCWS
Non-transient non-community water system
System record
How does Port of Shelton Johns Prairie compare with other water systems in Mason County?
By EPA's size categories, Port of Shelton Johns Prairie 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 non-transient non-community water system reports serving 430 people, so Port of Shelton Johns Prairie is about 24% below that figure.
What does “non-transient non-community water system” mean?
A non-transient non-community water system regularly serves at least 25 of the same people for more than six months a year, but not where they live. Schools, factories, office buildings and hospitals with their own supply are typical examples. Washington has 400 active non-transient non-community water systems, 8.5% of the state's 4,705 active systems. Purchased groundwater means the system buys groundwater from another public water system rather than drawing its own. 53 Washington systems (1.1%) list purchased groundwater as their primary source.
Who owns and regulates Port of Shelton Johns Prairie?
EPA lists Port of Shelton Johns Prairie as owned by a local government. 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. 64 of the 240 active systems in Mason County (27%) are also owned by a local government.
Does Port of Shelton Johns Prairie have drinking water violations?
Of the 12 most recent violations in EPA's records, 2 are health-based, and the most recent began in April 2000. The violations listed here began between October 1979 and April 2000. By type: 10 monitoring and reporting and 2 contaminant level above the legal limit. The contaminant or rule involved most often is Total coliform bacteria (TCR) (7 of them). EPA lists 11 as archived and 1 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 |
|---|---|---|---|---|
| 2000-04-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Archived |
| 1998-11-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Archived |
| 1998-01-01 | Monitoring and reportingInitial Tap Sampling for Pb and Cu · code 51 | Lead and Copper Rulecode 5000 | No | Resolved |
| 1996-11-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Archived |
| 1996-06-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Archived |
| 1995-11-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Archived |
| 1995-04-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Archived |
| 1993-09-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Archived |
| 1979-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | Cadmiumcode 1015 | No | Archived |
| 1979-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | Arseniccode 1005 | No | Archived |
| 1979-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | Mercurycode 1035 | No | Archived |
| 1979-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | Fluoridecode 1025 | 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.
Port of Shelton Johns Prairie: frequently asked questions
Who runs Port of Shelton Johns Prairie?
Port of Shelton Johns Prairie (PWSID WA5300620) is a non-transient non-community water system owned by a local government. It is regulated by the WA state drinking water program.
How many people does Port of Shelton Johns Prairie serve?
Port of Shelton Johns Prairie reports serving 328 people through 14 service connections in Mason County, Washington.
Where does Port of Shelton Johns Prairie get its water?
EPA SDWIS lists this system's primary water source as purchased groundwater. Purchased groundwater means the system buys groundwater from another public water system rather than drawing its own.
Does Port of Shelton Johns Prairie have any drinking water violations?
Of the 12 most recent violations in EPA's records, 2 are health-based, and the most recent began in April 2000. 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 Port of Shelton Johns Prairie'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, 2 are health-based, and the most recent began in April 2000. For current results, consult EPA ECHO, or the WA state drinking water program.
Where can I find Port of Shelton Johns Prairie's water quality report?
The annual Consumer Confidence Report requirement applies to community water systems. Port of Shelton Johns Prairie is a non-transient non-community water system, so it is not required to publish one; like every public water system, it must notify the people it serves about violations under EPA's public notification rules.
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, “Port of Shelton Johns Prairie, PWSID WA5300620, Washington”, https://aquacensus.com/water-systems/washington/port-of-shelton-johns-prairie-wa5300620 (data as of October 1, 2026).