Public water system · AK2260309
ActiveUnalaska Water System
At a glance
Unalaska Water System (PWSID AK2260309) is an active community water system in Aleutians West Census Area County, Alaska. It reports serving 9,400 people through 603 service connections. Its primary water source is surface water, and EPA lists it as owned by a local government. Of the 12 most recent violations in EPA's records, none is health-based, and the most recent began in October 2025.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
9,400
Service connections
603
Primary source
SW
Surface water
System type
CWS
Community water system
System record
How does Unalaska Water System compare with other water systems in Aleutians West Census Area County?
By EPA's size categories, Unalaska Water System is a medium system (3,301 to 10,000 people). Aleutians West Census Area County has 6 active public water systems, and Unalaska Water System is the largest of them by population served. Its population served is about 5.4 times the county average of 1,744 people per system, and accounts for 90% of the 10,464 people reported by systems filed under the county. Across Alaska, the 1,322 active systems average 653 people each. Nationally, the average active community water system reports serving 6,703 people, so Unalaska Water System is about 40% above 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. Alaska has 406 active community water systems, 31% of the state's 1,322 active systems. Surface water means the system draws its water from rivers, lakes, streams or reservoirs. 150 Alaska systems (11%) list surface water as their primary source.
Who owns and regulates Unalaska Water System?
EPA lists Unalaska Water System as owned by a local government. The AK state drinking water program is its primacy agency, the regulator with primary enforcement responsibility for the system under the Safe Drinking Water Act. 1 of the 6 active systems in Aleutians West Census Area County (17%) are also owned by a local government.
Does Unalaska 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 October 2025. The violations listed here began between May 2022 and October 2025. By type: 10 monitoring and reporting and 2 monitoring. The contaminant or rule involved most often is Haloacetic acids (HAA5) (2 of them). EPA lists 12 as resolved. 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 |
|---|---|---|---|---|
| 2025-10-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Haloacetic acids (HAA5)code 2456 | No | Resolved |
| 2025-10-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Total trihalomethanes (TTHM)code 2950 | No | Resolved |
| 2024-05-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Chlorinecode 0999 | No | Resolved |
| 2024-05-01 | Monitoring and reportingMonitoring of Treatment (SWTR-Unfilt/GWR) · code 31 | Surface Water Treatment Rulecode 0200 | No | Resolved |
| 2024-05-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2024-01-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Haloacetic acids (HAA5)code 2456 | No | Resolved |
| 2024-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | No | Resolved |
| 2024-01-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Total trihalomethanes (TTHM)code 2950 | No | Resolved |
| 2023-10-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Carbon, totalcode 2920 | No | Resolved |
| 2023-07-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Carbon, totalcode 2920 | No | Resolved |
| 2022-05-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2022-05-01 | Monitoring and reportingMonitoring of Treatment (SWTR-Unfilt/GWR) · code 31 | Surface Water Treatment Rulecode 0200 | 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.
Unalaska Water System: frequently asked questions
Who runs Unalaska Water System?
Unalaska Water System (PWSID AK2260309) is a community water system owned by a local government. It is regulated by the AK state drinking water program.
How many people does Unalaska Water System serve?
Unalaska Water System reports serving 9,400 people through 603 service connections in Aleutians West Census Area County, Alaska.
Where does Unalaska Water System get its water?
EPA SDWIS lists this system's primary water source as surface water. Surface water means the system draws its water from rivers, lakes, streams or reservoirs.
Does Unalaska 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 October 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 Unalaska 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 October 2025. For current results, consult the system's annual water quality report, EPA ECHO, or the AK state drinking water program.
Where can I find Unalaska Water System's water quality report?
As a community water system, Unalaska 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 Aleutians West Census Area County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Offshore Systems, Dutch Harbor | Aleutians West Census Area | 535 | Non-transient non-community | Surface water |
| Saint Paul Water System | Aleutians West Census Area | 380 | Community | Groundwater |
| Saint George Water System | Aleutians West Census Area | 65 | Community | Groundwater |
| Atka | Aleutians West Census Area | 50 | Community | Surface water |
| Nikolski Village | Aleutians West Census Area | 34 | Community | Groundwater under influence of 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, “Unalaska Water System, PWSID AK2260309, Alaska”, https://aquacensus.com/water-systems/alaska/unalaska-water-system-ak2260309 (data as of October 1, 2026).