Public water system · WA5388700
ActiveTonasket Water System
At a glance
Tonasket Water System (PWSID WA5388700) is an active community water system in Okanogan County, Washington. It reports serving 2,398 people through 602 service connections. Its primary water source is groundwater, and EPA lists it as owned by a local government. Of the 12 most recent violations in EPA's records, 4 are health-based, and the most recent began in October 2020.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
2,398
Service connections
602
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Tonasket Water System compare with other water systems in Okanogan County?
By EPA's size categories, Tonasket Water System is a small system (501 to 3,300 people). Okanogan County has 119 active public water systems, and Tonasket Water System is the 5th-largest of them by population served. Its population served is about 6.3 times the county average of 383 people per system, and accounts for 5.3% of the 45,608 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 Tonasket Water System is about 64% 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 Tonasket Water System?
EPA lists Tonasket Water System 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. 16 of the 119 active systems in Okanogan County (13%) are also owned by a local government.
Does Tonasket Water System have drinking water violations?
Of the 12 most recent violations in EPA's records, 4 are health-based, and the most recent began in October 2020. The violations listed here began between October 1979 and October 2020. By type: 5 monitoring and reporting, 4 contaminant level above the legal limit, 2 monitoring and 1 public notice, recordkeeping or other. The contaminant or rule involved most often is Total coliform bacteria (TCR) (6 of them). EPA lists 8 as archived and 4 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 |
|---|---|---|---|---|
| 2020-10-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2019-10-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2018-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2014-05-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 1998-11-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Archived |
| 1997-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Archived |
| 1996-11-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Archived |
| 1995-11-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Archived |
| 1991-10-01 | Monitoring and reportingMonitoring, Repeat Minor (TCR) · code 26 | Total coliform bacteria (TCR)code 3100 | No | Archived |
| 1979-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | Chromiumcode 1020 | 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.
Tonasket Water System: frequently asked questions
Who runs Tonasket Water System?
Tonasket Water System (PWSID WA5388700) is a community water system owned by a local government. It is regulated by the WA state drinking water program.
How many people does Tonasket Water System serve?
Tonasket Water System reports serving 2,398 people through 602 service connections in Okanogan County, Washington.
Where does Tonasket 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 Tonasket Water System have any drinking water violations?
Of the 12 most recent violations in EPA's records, 4 are health-based, and the most recent began in October 2020. 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 Tonasket 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, 4 are health-based, and the most recent began in October 2020. For current results, consult the system's annual water quality report, EPA ECHO, or the WA state drinking water program.
Where can I find Tonasket Water System's water quality report?
As a community water system, Tonasket Water System 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 Okanogan County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Omak City of | Okanogan | 4,940 | Community | Groundwater |
| Brewster City of | Okanogan | 3,843 | Community | Groundwater |
| Okanogan Water Department City of | Okanogan | 3,817 | Community | Groundwater |
| Oroville City of | Okanogan | 3,256 | Community | Groundwater |
| Pearrygin Lake State Park - Both Cg | Okanogan | 2,103 | Transient non-community | Groundwater |
| Okanogan Neighbors | Okanogan | 1,600 | Transient non-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, “Tonasket Water System, PWSID WA5388700, Washington”, https://aquacensus.com/water-systems/washington/tonasket-water-system-wa5388700 (data as of October 1, 2026).