Community Water System · PWS AK2260309
Unalaska Water System
Unalaska, Alaska 99685 - drinking water served from surface water sources to 9,400 people, tracked in EPA SDWIS and UCMR5.
- 9,400
- People served
- 398
- EPA violations
- 3
- Health-based
- No PFAS
- UCMR5 result
The verdict
EPA records 398 drinking-water violations at Unalaska Water System, 1% of them health-based - above the Alaska per-system average.
- 398
- Total EPA violations on record
- 1%
- Health-based (MCL / treatment failure)
- 9,400
- People served by this system
- 0
- PFAS compounds detected (UCMR5)
Water Quality Snapshot: Unalaska Water System
Unalaska Water System is a local-owned community water system that delivers drinking water to 9,400 residents in Unalaska, Alaska (Aleutians West Census Area County) through 603 service connections. Its water is drawn from surface water sources. EPA's Safe Drinking Water Information System records 398 total violations for this system , of which 3 (1%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 288 monitoring and reporting violations are on file. The most recent violation on record dates to 2024.
The most frequently cited contaminant at this system is Surface Water Treatment Rule, recorded in 12 violations (MR). This system was sampled under EPA's UCMR5 PFAS monitoring program and no PFAS compounds were detected above the minimum reporting level.
Across Alaska, EPA tracks 1,326 public water systems serving 862,218 people, with 267,144 cumulative violations and 13,963 health-based violations on record. About 98% of systems in the state carry at least one violation, and state-wide the average per system is 201.5 violations. Statewide, 10 of 30 UCMR5-tested systems have reported PFAS detections (33.3%).
Unalaska Water System's 398 violations sit above the Alaska average.
All figures above are sourced directly from EPA SDWIS and UCMR5 public data releases and are updated as EPA publishes new reporting cycles.
System Details
- System Type
- Community
- Owner Type
- Local
- Connections
- 603
- County
- Aleutians West Census Area
- School/Daycare
- No
- MCL Violations
- 0
- Monitoring Violations
- 288
- Treatment Tech Violations
- 3
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| Surface Water Treatment Rule | MR | 12 | 2024 |
| Nitrate | MR | 11 | 2024 |
| Coliform (TCR) | MR | 9 | 2015 |
| Arsenic | MR | 8 | 2003 |
| Chlorine | MR | 8 | 2024 |
| Barium | MR | 7 | 1992 |
| Cadmium | MR | 7 | 1992 |
| Chromium | MR | 7 | 1992 |
| Selenium | MR | 7 | 1992 |
| Fluoride | MR | 7 | 1992 |
| Mercury | MR | 7 | 1992 |
| Methoxychlor | MR | 6 | 2001 |
| Toxaphene | MR | 6 | 2001 |
| 2,4,5-TP | MR | 6 | 2001 |
| 2,4-D | MR | 6 | 2001 |
| BHC-GAMMA | MR | 6 | 2001 |
| Endrin | MR | 6 | 2001 |
| p-Dichlorobenzene | MR | 5 | 1997 |
| Carbon tetrachloride | MR | 5 | 1997 |
| CHLOROBENZENE | MR | 5 | 1997 |
| Toluene | MR | 5 | 1997 |
| Tetrachloroethylene | MR | 5 | 1997 |
| Ethylbenzene | MR | 5 | 1997 |
| 1,1-Dichloroethylene | MR | 5 | 1997 |
| Trichloroethylene | MR | 5 | 1997 |
| 1,2-Dichloroethane | MR | 5 | 1997 |
| 1,1,2-Trichloroethane | MR | 5 | 1997 |
| 1,1,1-Trichloroethane | MR | 5 | 1997 |
| o-Dichlorobenzene | MR | 5 | 1997 |
| 1,2-Dichloropropane | MR | 5 | 1997 |
PFAS Testing Results (UCMR5)
Results from EPA's Fifth Unregulated Contaminant Monitoring Rule. 0 of 232 samples detected PFAS.
| Contaminant | Date | Result | MRL | Status |
|---|---|---|---|---|
| PFOS | 6/19/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| HFPO-DA | 6/19/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| ADONA | 6/19/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| 9Cl-PF3ONS | 6/19/2023 | <2.00 ppt | 2.00 ppt | Not Detected |
| 11Cl-PF3OUdS | 6/19/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFUnA | 6/19/2023 | <2.00 ppt | 2.00 ppt | Not Detected |
| PFHxA | 6/19/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFBS | 6/19/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHpA | 6/19/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFNA | 6/19/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFDA | 6/19/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFOA | 6/19/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFBA | 6/19/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| NEtFOSAA | 6/19/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFHxS | 6/19/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFTrDA | 6/19/2023 | <7.00 ppt | 7.00 ppt | Not Detected |
| PFHpS | 6/19/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFPeS | 6/19/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| NFDHA | 6/19/2023 | <20.00 ppt | 20.00 ppt | Not Detected |
| PFTA | 6/19/2023 | <8.00 ppt | 8.00 ppt | Not Detected |
| PFDoA | 6/19/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| 6:2 FTS | 6/19/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFEESA | 6/19/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFMBA | 6/19/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFPeA | 6/19/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFMPA | 6/19/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| 8:2 FTS | 6/19/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| 4:2 FTS | 6/19/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| NMeFOSAA | 6/19/2023 | <6.00 ppt | 6.00 ppt | Not Detected |
| PFTrDA | 6/13/2024 | <7.00 ppt | 7.00 ppt | Not Detected |
| PFTA | 6/13/2024 | <8.00 ppt | 8.00 ppt | Not Detected |
| NEtFOSAA | 6/13/2024 | <5.00 ppt | 5.00 ppt | Not Detected |
| NMeFOSAA | 6/13/2024 | <6.00 ppt | 6.00 ppt | Not Detected |
| PFOS | 12/29/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| ADONA | 12/29/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFBS | 12/29/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHpA | 12/29/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHxS | 12/29/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFNA | 12/29/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| 8:2 FTS | 12/29/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| NEtFOSAA | 12/29/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFTrDA | 12/29/2023 | <7.00 ppt | 7.00 ppt | Not Detected |
| PFTA | 12/29/2023 | <8.00 ppt | 8.00 ppt | Not Detected |
| PFHpS | 12/29/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFPeS | 12/29/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| NFDHA | 12/29/2023 | <20.00 ppt | 20.00 ppt | Not Detected |
| PFEESA | 12/29/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFMBA | 12/29/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| 11Cl-PF3OUdS | 12/29/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFMPA | 12/29/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
Verify This Water System
The figures above are aggregated from EPA's public databases. To verify the underlying records, or to file a complaint, request a Consumer Confidence Report, or check current monitoring status, go directly to the federal and state regulators that enforce the Safe Drinking Water Act for Unalaska Water System.
EPA SDWIS, Federal Reports
EPA's Safe Drinking Water Information System (SDWIS) holds the federal compliance record for every regulated public water system. Open the system-level report by PWS ID:
View PWS ID AK2260309 on SDWISSource: EPA SDWIS Federal Reports Search
Alaska Drinking Water Authority
Alaska's primacy agency administers the Safe Drinking Water Act locally. Search EPA SDWIS for the current state contact, or use the state's public health or environment department portal.
Find AK regulator via EPA SDWISViolation Timeline
Each row links to the EPA SDWIS public record for verification. Cross-reference the contaminant code on EPA's federal report to see violation dates, return-to-compliance status, and enforcement actions.
| Year (latest) | Contaminant | Category | Count | EPA Record |
|---|---|---|---|---|
| 2024 | Surface Water Treatment Rule | MR | 12 | SDWIS / AK2260309 / 0200 |
| 2024 | Nitrate | MR | 11 | SDWIS / AK2260309 / 1040 |
| 2024 | Chlorine | MR | 8 | SDWIS / AK2260309 / 0999 |
| 2024 | Revised Total Coliform Rule | MON | 4 | SDWIS / AK2260309 / 8000 |
| 2024 | Total Haloacetic Acids (HAA5) | MR | 1 | SDWIS / AK2260309 / 2456 |
| 2024 | TTHM | MR | 1 | SDWIS / AK2260309 / 2950 |
| 2023 | CARBON, TOTAL | MR | 2 | SDWIS / AK2260309 / 2920 |
| 2015 | Coliform (TCR) | MR | 9 | SDWIS / AK2260309 / 3100 |
| 2004 | Surface Water Treatment Rule | TT | 3 | SDWIS / AK2260309 / 0200 |
| 2003 | Arsenic | MR | 8 | SDWIS / AK2260309 / 1005 |
| 2001 | Methoxychlor | MR | 6 | SDWIS / AK2260309 / 2015 |
| 2001 | Toxaphene | MR | 6 | SDWIS / AK2260309 / 2020 |
| 2001 | 2,4,5-TP | MR | 6 | SDWIS / AK2260309 / 2110 |
| 2001 | 2,4-D | MR | 6 | SDWIS / AK2260309 / 2105 |
| 2001 | BHC-GAMMA | MR | 6 | SDWIS / AK2260309 / 2010 |
How Unalaska Water System Compares
Cross-reference this system's record against state averages and the federal MCL framework for context.
| Metric | Unalaska Water System | Alaska avg | Federal benchmark |
|---|---|---|---|
| Total violations | 398 | 201.5 | SDWA compliance, any non-zero count is a recorded breach |
| Health-based violations | 3 | 10.5 | Indicates a contaminant exceeded a federal MCL |
| PFAS detection | None | 33.3% | EPA final rule (2024): PFOA/PFOS MCL = 4.0 ppt |
| Population served | 9,400 | 650 | Sizing context for compliance burden |
Sources: EPA SDWIS and EPA National Primary Drinking Water Regulations (40 CFR Part 141). State averages computed across 1,326 regulated public water systems in Alaska.
Federal MCL reference, Safe Drinking Water Act thresholds ▼
| Contaminant | Federal MCL / Action Level | Note |
|---|---|---|
| Lead | 0 mg/L (Action Level: 0.015 mg/L) | Lead and Copper Rule treatment technique |
| Arsenic | 0.010 mg/L (10 ppb) | Health-based MCL since 2006 |
| Total Coliform | Treatment technique (RTCR) | Indicator organism, monitoring trigger |
| PFOA / PFOS (PFAS) | 4.0 ppt each (final 2024 rule) | Compliance deadline 2029 (EPA proposed extending to 2031, not yet final as of May 2026) |
| Nitrate (as N) | 10 mg/L | Acute health risk for infants |
Frequently Asked Questions
Is Unalaska Water System water safe to drink? ▼
How many people does Unalaska Water System serve? ▼
What type of violations does Unalaska Water System have? ▼
Has PFAS been detected in Unalaska Water System water? ▼
What water source does Unalaska Water System use? ▼
Where does this data come from? ▼
Read our methodology - how this data is sourced, computed, and verified.
Every figure on PlainWater is rendered directly from EPA SDWIS drinking-water data, no number is typed in by an editor. This system's figures are rendered directly from EPA SDWIS data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.