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Community Water System · PWS AK2240472

Tyonek Water System

Tyonek, Alaska 99682 - drinking water served from groundwater sources to 206 people, tracked in EPA SDWIS and UCMR5.

206
People served
788
EPA violations
60
Health-based
Untested
UCMR5 result

The verdict

EPA records 788 drinking-water violations at Tyonek Water System, 8% of them health-based - above the Alaska per-system average.

788
Total EPA violations on record
8%
Health-based (MCL / treatment failure)
206
People served by this system
N/A
PFAS compounds detected (UCMR5)

Water Quality Snapshot: Tyonek Water System

Tyonek Water System is a native american-owned community water system that delivers drinking water to 206 residents in Tyonek, Alaska (Kenai Peninsula Borough County) through 97 service connections. Its water is drawn from groundwater sources. EPA's Safe Drinking Water Information System records 788 total violations for this system , of which 60 (8%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 529 monitoring and reporting violations are on file. The most recent violation on record dates to 2025.

The most frequently cited contaminant at this system is Surface Water Treatment Rule, recorded in 64 violations (MR). This system has not yet been sampled under EPA's UCMR5 PFAS monitoring program, so no PFAS detection data is available here.

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%).

Tyonek Water System's 788 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.

Population Served
206
Total Violations
788
Health-Based Violations
60
Water Source
Groundwater

System Details

System Type
Community
Owner Type
Native American
Connections
97
County
Kenai Peninsula Borough
School/Daycare
No
MCL Violations
6
Monitoring Violations
529
Treatment Tech Violations
54

Violation History

Contaminant violations recorded by EPA.

Contaminant Category Count Latest
Surface Water Treatment Rule MR 64 2005
Coliform (TCR) MR 50 2015
Lead and Copper Rule MR 48 2025
Surface Water Treatment Rule TT 47 2005
Nitrate MR 20 2000
Arsenic MR 17 2019
Consumer Confidence Rule Other 15 2020
Barium MR 13 1991
Chromium MR 13 1991
Cadmium MR 13 1991
Fluoride MR 13 1991
Selenium MR 13 1991
Mercury MR 13 1991
p-Dichlorobenzene MR 9 2007
Carbon tetrachloride MR 9 2007
1,1-Dichloroethylene MR 9 2007
1,2-Dichloroethane MR 9 2007
Benzene MR 9 2007
1,1,1-Trichloroethane MR 9 2007
Trichloroethylene MR 9 2007
o-Dichlorobenzene MR 8 2007
CHLOROBENZENE MR 8 2007
Styrene MR 8 2007
Ethylbenzene MR 8 2007
cis-1,2-Dichloroethylene MR 8 2007
Toluene MR 8 2007
Tetrachloroethylene MR 8 2007
1,2-Dichloropropane MR 8 2007
Xylenes, Total MR 8 2007
trans-1,2-Dichloroethylene MR 8 2007

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 Tyonek Water System.

Federal Source of Truth

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 AK2240472 on SDWIS

Source: EPA SDWIS Federal Reports Search

State Regulator

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 SDWIS

Violation 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
2025 Lead and Copper Rule MR 48 SDWIS / AK2240472 / 5000
2023 E. COLI MR 1 SDWIS / AK2240472 / 3014
2021 Revised Total Coliform Rule MON 7 SDWIS / AK2240472 / 8000
2021 Chlorine MR 6 SDWIS / AK2240472 / 0999
2020 Consumer Confidence Rule Other 15 SDWIS / AK2240472 / 7000
2019 Arsenic MR 17 SDWIS / AK2240472 / 1005
2016 Revised Total Coliform Rule Other 2 SDWIS / AK2240472 / 8000
2015 Coliform (TCR) MR 50 SDWIS / AK2240472 / 3100
2007 p-Dichlorobenzene MR 9 SDWIS / AK2240472 / 2969
2007 Carbon tetrachloride MR 9 SDWIS / AK2240472 / 2982
2007 1,1-Dichloroethylene MR 9 SDWIS / AK2240472 / 2977
2007 1,2-Dichloroethane MR 9 SDWIS / AK2240472 / 2980
2007 Benzene MR 9 SDWIS / AK2240472 / 2990
2007 1,1,1-Trichloroethane MR 9 SDWIS / AK2240472 / 2981
2007 Trichloroethylene MR 9 SDWIS / AK2240472 / 2984

How Tyonek Water System Compares

Cross-reference this system's record against state averages and the federal MCL framework for context.

Metric Tyonek Water System Alaska avg Federal benchmark
Total violations 788 201.5 SDWA compliance, any non-zero count is a recorded breach
Health-based violations 60 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 206 650 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 Tyonek Water System water safe to drink? ▼
Tyonek Water System (PWS ID: AK2240472) has 788 recorded violations in the EPA SDWIS database. No PFAS contamination was detected in UCMR5 testing. This system serves 206 people using Groundwater sources.
How many people does Tyonek Water System serve? ▼
Tyonek Water System serves 206 people in Tyonek, Alaska. It is a Native American-owned system using Groundwater water sources with 97 service connections.
What type of violations does Tyonek Water System have? ▼
Tyonek Water System has 788 total violations: 60 health-based violations (MCL exceedances or treatment failures), 529 monitoring/reporting violations, and 54 treatment technique violations. Health-based violations indicate contaminant levels exceeded EPA safe limits.
Has PFAS been detected in Tyonek Water System water? ▼
No PFAS testing data is available for Tyonek Water System under the EPA's UCMR5 monitoring program.
What water source does Tyonek Water System use? ▼
Tyonek Water System uses Groundwater as its primary water source. It is classified as a Community Water System (CWS), serving residential populations year-round.
Where does this data come from? ▼
All data comes from the EPA Safe Drinking Water Information System (SDWIS) and the UCMR5 PFAS monitoring program. SDWIS tracks compliance for all public water systems regulated under the Safe Drinking Water Act.
Data Sources: EPA Safe Drinking Water Information System (SDWIS), Q4 2025. This data is provided for informational purposes only.

Read our methodology - how this data is sourced, computed, and verified.

Data sourced from EPA SDWIS and UCMR5 PFAS monitoring data. See our methodology for details. Retrieved and formatted by PlainWater Editorial

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.