Public water system · WA5390050
ActiveTwisp Town of
At a glance
Town of Twisp (PWSID WA5390050) is an active community water system in Okanogan County, Washington. It reports serving 1,173 people through 675 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, one is health-based, and the most recent began in January 2022.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
1,173
Service connections
675
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Town of Twisp compare with other water systems in Okanogan County?
By EPA's size categories, Town of Twisp is a small system (501 to 3,300 people). Okanogan County has 119 active public water systems. Its population served is about 3.1 times the county average of 383 people per system, and accounts for 2.6% 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 Town of Twisp 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 Town of Twisp?
EPA lists Town of Twisp 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 Town of Twisp have drinking water violations?
Of the 12 most recent violations in EPA's records, one is health-based, and the most recent began in January 2022. The violations listed here began between January 2005 and January 2022. By type: 10 monitoring and reporting, 1 monitoring and 1 contaminant level above the legal limit. The contaminant or rule involved most often is Nitrate (5 of them). EPA lists 11 as resolved and 1 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 |
|---|---|---|---|---|
| 2022-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | No | Resolved |
| 2022-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | No | Resolved |
| 2020-05-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2007-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | No | Resolved |
| 2007-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | No | Resolved |
| 2005-10-01 | 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 | Alachlor (Lasso)code 2051 | No | Resolved |
| 2005-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Atrazinecode 2050 | No | Resolved |
| 2005-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Simazinecode 2037 | No | Resolved |
| 2005-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Hexachlorocyclopentadienecode 2042 | No | Resolved |
| 2005-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Endrincode 2005 | No | Resolved |
| 2005-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | No | Resolved |
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.
Town of Twisp: frequently asked questions
Who runs Town of Twisp?
Town of Twisp (PWSID WA5390050) is a community water system owned by a local government. It is regulated by the WA state drinking water program.
How many people does Town of Twisp serve?
Town of Twisp reports serving 1,173 people through 675 service connections in Okanogan County, Washington.
Where does Town of Twisp 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 Town of Twisp have any drinking water violations?
Of the 12 most recent violations in EPA's records, one is health-based, and the most recent began in January 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 Town of Twisp'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, one is health-based, and the most recent began in January 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 Town of Twisp's water quality report?
As a community water system, Town of Twisp 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 |
| Tonasket Water System | Okanogan | 2,398 | Community | Groundwater |
| Pearrygin Lake State Park - Both Cg | Okanogan | 2,103 | 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, “Twisp Town of, PWSID WA5390050, Washington”, https://aquacensus.com/water-systems/washington/twisp-town-of-wa5390050 (data as of October 1, 2026).