Public water system · WA5364401
ActiveWhitehorse Mercantile Water System
At a glance
Whitehorse Mercantile Water System (PWSID WA5364401) is an active transient non-community water system in Snohomish County, Washington. It reports serving 930 people through 1 service connection. 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 November 2025.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
930
Service connections
1
Primary source
GW
Groundwater
System type
TNCWS
Transient non-community water system
System record
How does Whitehorse Mercantile Water System compare with other water systems in Snohomish County?
By EPA's size categories, Whitehorse Mercantile Water System is a small system (501 to 3,300 people). Snohomish County has 167 active public water systems. Its population served is well below the county average of 6,200 people per system, and accounts for less than 0.1% of the 1,035,433 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 Whitehorse Mercantile Water System is about 6.5 times 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 Whitehorse Mercantile Water System?
EPA lists Whitehorse Mercantile Water System 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. 126 of the 167 active systems in Snohomish County (75%) are also privately owned.
Does Whitehorse Mercantile Water System have drinking water violations?
Of the 12 most recent violations in EPA's records, none is health-based, and the most recent began in November 2025. The violations listed here began between August 1995 and November 2025. 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 7 as resolved and 5 as archived. 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. 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 |
|---|---|---|---|---|
| 2025-11-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2025-08-01 | 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 |
| 2014-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | No | Resolved |
| 2012-10-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 2009-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | No | Resolved |
| 2007-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | No | Resolved |
| 1999-02-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Archived |
| 1997-11-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Archived |
| 1997-08-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Archived |
| 1995-12-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Archived |
| 1995-08-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | 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.
Whitehorse Mercantile Water System: frequently asked questions
Who runs Whitehorse Mercantile Water System?
Whitehorse Mercantile Water System (PWSID WA5364401) is a transient non-community water system privately owned. It is regulated by the WA state drinking water program.
How many people does Whitehorse Mercantile Water System serve?
Whitehorse Mercantile Water System reports serving 930 people through 1 service connection in Snohomish County, Washington.
Where does Whitehorse Mercantile Water System 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 Whitehorse Mercantile Water System 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 November 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 Whitehorse Mercantile Water System'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 November 2025. For current results, consult EPA ECHO, or the WA state drinking water program.
Where can I find Whitehorse Mercantile Water System's water quality report?
The annual Consumer Confidence Report requirement applies to community water systems. Whitehorse Mercantile Water System 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 Snohomish County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Alderwood Water District | Snohomish | 245,715 | Community | Purchased surface water |
| Everett Public Works Dept. City of | Snohomish | 215,774 | Community | Surface water |
| Marysville Utilities | Snohomish | 88,582 | Community | Purchased surface water |
| Lynnwood City of | Snohomish | 68,204 | Community | Purchased surface water |
| Sno PUD 1 - Lake Stevens | Snohomish | 67,710 | Community | Purchased surface water |
| Silver Lake Water & Sewer District | Snohomish | 65,033 | Community | Purchased surface water |
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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, “Whitehorse Mercantile Water System, PWSID WA5364401, Washington”, https://aquacensus.com/water-systems/washington/whitehorse-mercantile-water-system-wa5364401 (data as of October 1, 2026).