Public water system · WA5391938
ActiveVista Knoll Water Co Inc.
At a glance
Vista Knoll Water Co Inc. (PWSID WA5391938) is an active transient non-community water system in Mason County, Washington. It reports serving 22 people through 33 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 July 2022.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
22
Service connections
33
Primary source
GW
Groundwater
System type
TNCWS
Transient non-community water system
System record
How does Vista Knoll Water Co Inc. compare with other water systems in Mason County?
By EPA's size categories, Vista Knoll Water Co Inc. 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 transient non-community water system reports serving 144 people, so Vista Knoll Water Co Inc. is well below that figure.
What does “transient non-community water system” mean?
A transient non-community water system serves places where people do not stay long, such as gas stations and campgrounds, and regularly serves at least 25 people a day for at least 60 days a year. Washington has 1,913 active transient non-community water systems, 41% 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 Vista Knoll Water Co Inc.?
EPA lists Vista Knoll Water Co Inc. 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 Vista Knoll Water Co Inc. have drinking water violations?
Of the 12 most recent violations in EPA's records, none is health-based, and the most recent began in July 2022. The violations listed here began between October 1979 and July 2022. By type: 10 monitoring and reporting and 2 monitoring. The contaminant or rule involved most often is Total coliform bacteria (TCR) (6 of them). EPA lists 9 as archived and 3 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 |
| 2021-04-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2018-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | No | Resolved |
| 2005-05-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Archived |
| 2004-11-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Archived |
| 1994-03-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Archived |
| 1994-01-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Archived |
| 1993-12-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Archived |
| 1993-11-01 | 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 | Mercurycode 1035 | No | Archived |
| 1979-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | Arseniccode 1005 | No | Archived |
| 1979-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | Chromiumcode 1020 | 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.
Vista Knoll Water Co Inc.: frequently asked questions
Who runs Vista Knoll Water Co Inc.?
Vista Knoll Water Co Inc. (PWSID WA5391938) is a transient non-community water system privately owned. It is regulated by the WA state drinking water program.
How many people does Vista Knoll Water Co Inc. serve?
Vista Knoll Water Co Inc. reports serving 22 people through 33 service connections in Mason County, Washington.
Where does Vista Knoll Water Co Inc. 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 Vista Knoll Water Co Inc. 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 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 Vista Knoll Water Co Inc.'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 July 2022. For current results, consult EPA ECHO, or the WA state drinking water program.
Where can I find Vista Knoll Water Co Inc.'s water quality report?
The annual Consumer Confidence Report requirement applies to community water systems. Vista Knoll Water Co Inc. is a 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, “Vista Knoll Water Co Inc., PWSID WA5391938, Washington”, https://aquacensus.com/water-systems/washington/vista-knoll-water-co-inc-wa5391938 (data as of October 1, 2026).