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Community Water System · PWS MT0003136

West Yellowstone Town Of

West Yellowstone, Montana 59758 - drinking water served from groundwater sources to 9,899 people, tracked in EPA SDWIS and UCMR5.

9,899
People served
203
EPA violations
4
Health-based
No PFAS
UCMR5 result

The verdict

EPA records 203 drinking-water violations at West Yellowstone Town Of, 2% of them health-based - above the Montana per-system average.

203
Total EPA violations on record
2%
Health-based (MCL / treatment failure)
9,899
People served by this system
0
PFAS compounds detected (UCMR5)

Water Quality Snapshot: West Yellowstone Town Of

West Yellowstone Town Of is a local-owned community water system that delivers drinking water to 9,899 residents in West Yellowstone, Montana (Gallatin County) through 628 service connections. Its water is drawn from groundwater sources. EPA's Safe Drinking Water Information System records 203 total violations for this system , of which 4 (2%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 189 monitoring and reporting violations are on file. The most recent violation on record dates to 2021.

The most frequently cited contaminant at this system is Coliform (TCR), recorded in 27 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 Montana, EPA tracks 2,263 public water systems serving 1,112,267 people, with 297,270 cumulative violations and 25,922 health-based violations on record. About 95% of systems in the state carry at least one violation, and state-wide the average per system is 131.4 violations. Statewide, 28 of 45 UCMR5-tested systems have reported PFAS detections (62.2%).

West Yellowstone Town Of's 203 violations sit above the Montana 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
9,899
Total Violations
203
Health-Based Violations
4
Water Source
Groundwater

System Details

System Type
Community
Owner Type
Local
Connections
628
County
Gallatin
School/Daycare
No
MCL Violations
1
Monitoring Violations
189
Treatment Tech Violations
3

Violation History

Contaminant violations recorded by EPA.

Contaminant Category Count Latest
Coliform (TCR) MR 27 2014
Arsenic MR 15 2021
E. COLI MR 13 2019
Fluoride MR 13 2021
Consumer Confidence Rule Other 10 2017
Lead and Copper Rule MR 7 2018
Hexachlorocyclopentadiene MR 7 2017
Revised Total Coliform Rule MON 6 2016
Endrin MR 4 2017
BHC-GAMMA MR 4 2017
Methoxychlor MR 4 2017
Di(2-ethylhexyl) adipate MR 4 2017
Simazine MR 4 2017
Di(2-ethylhexyl) phthalate MR 4 2017
Carbofuran MR 4 2017
Atrazine MR 4 2017
Heptachlor MR 4 2017
2,4-D MR 4 2017
2,4,5-TP MR 4 2017
HEXACHLOROBENZENE MR 4 2017
Benzo(a)pyrene MR 4 2017
Dalapon MR 4 2017
Heptachlor epoxide MR 4 2017
LASSO MR 4 2017
Pentachlorophenol MR 4 2017
Toxaphene MR 4 2017
Chlordane MR 4 2017
Dinoseb MR 4 2017
OXAMYL MR 4 2017
Picloram MR 4 2017

PFAS Testing Results (UCMR5)

Results from EPA's Fifth Unregulated Contaminant Monitoring Rule. 0 of 174 samples detected PFAS.

Contaminant Date Result MRL Status
PFBS 4/23/2024 <3.00 ppt 3.00 ppt Not Detected
PFHxA 4/23/2024 <3.00 ppt 3.00 ppt Not Detected
6:2 FTS 4/23/2024 <5.00 ppt 5.00 ppt Not Detected
8:2 FTS 4/23/2024 <5.00 ppt 5.00 ppt Not Detected
PFBA 4/23/2024 <5.00 ppt 5.00 ppt Not Detected
HFPO-DA 4/23/2024 <5.00 ppt 5.00 ppt Not Detected
ADONA 4/23/2024 <3.00 ppt 3.00 ppt Not Detected
4:2 FTS 4/23/2024 <3.00 ppt 3.00 ppt Not Detected
PFHpA 4/23/2024 <3.00 ppt 3.00 ppt Not Detected
PFHxS 4/23/2024 <3.00 ppt 3.00 ppt Not Detected
PFNA 4/23/2024 <4.00 ppt 4.00 ppt Not Detected
PFOS 4/23/2024 <4.00 ppt 4.00 ppt Not Detected
PFOA 4/23/2024 <4.00 ppt 4.00 ppt Not Detected
NMeFOSAA 4/23/2024 <6.00 ppt 6.00 ppt Not Detected
PFDoA 4/23/2024 <3.00 ppt 3.00 ppt Not Detected
PFHpS 4/23/2024 <3.00 ppt 3.00 ppt Not Detected
PFUnA 4/23/2024 <2.00 ppt 2.00 ppt Not Detected
11Cl-PF3OUdS 4/23/2024 <5.00 ppt 5.00 ppt Not Detected
PFDA 4/23/2024 <3.00 ppt 3.00 ppt Not Detected
PFPeA 4/23/2024 <3.00 ppt 3.00 ppt Not Detected
PFMBA 4/23/2024 <3.00 ppt 3.00 ppt Not Detected
PFEESA 4/23/2024 <3.00 ppt 3.00 ppt Not Detected
NFDHA 4/23/2024 <20.00 ppt 20.00 ppt Not Detected
9Cl-PF3ONS 4/23/2024 <2.00 ppt 2.00 ppt Not Detected
PFTA 4/23/2024 <8.00 ppt 8.00 ppt Not Detected
NEtFOSAA 4/23/2024 <5.00 ppt 5.00 ppt Not Detected
PFTrDA 4/23/2024 <7.00 ppt 7.00 ppt Not Detected
PFMPA 4/23/2024 <4.00 ppt 4.00 ppt Not Detected
PFPeS 4/23/2024 <4.00 ppt 4.00 ppt Not Detected
PFTA 4/23/2024 <8.00 ppt 8.00 ppt Not Detected
PFTrDA 4/23/2024 <7.00 ppt 7.00 ppt Not Detected
NEtFOSAA 4/23/2024 <5.00 ppt 5.00 ppt Not Detected
NMeFOSAA 4/23/2024 <6.00 ppt 6.00 ppt Not Detected
PFDoA 4/23/2024 <3.00 ppt 3.00 ppt Not Detected
HFPO-DA 4/23/2024 <5.00 ppt 5.00 ppt Not Detected
PFBS 4/23/2024 <3.00 ppt 3.00 ppt Not Detected
PFHpA 4/23/2024 <3.00 ppt 3.00 ppt Not Detected
PFHxS 4/23/2024 <3.00 ppt 3.00 ppt Not Detected
PFNA 4/23/2024 <4.00 ppt 4.00 ppt Not Detected
PFOS 4/23/2024 <4.00 ppt 4.00 ppt Not Detected
PFDA 4/23/2024 <3.00 ppt 3.00 ppt Not Detected
PFBA 4/23/2024 <5.00 ppt 5.00 ppt Not Detected
6:2 FTS 4/23/2024 <5.00 ppt 5.00 ppt Not Detected
4:2 FTS 4/23/2024 <3.00 ppt 3.00 ppt Not Detected
8:2 FTS 4/23/2024 <5.00 ppt 5.00 ppt Not Detected
PFHxA 4/23/2024 <3.00 ppt 3.00 ppt Not Detected
PFPeS 4/23/2024 <4.00 ppt 4.00 ppt Not Detected
PFOA 4/23/2024 <4.00 ppt 4.00 ppt Not Detected
PFHpS 4/23/2024 <3.00 ppt 3.00 ppt Not Detected
PFUnA 4/23/2024 <2.00 ppt 2.00 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 West Yellowstone Town Of.

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 MT0003136 on SDWIS

Source: EPA SDWIS Federal Reports Search

State Regulator

Montana Drinking Water Authority

Montana'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 MT 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
2021 Arsenic MR 15 SDWIS / MT0003136 / 1005
2021 Fluoride MR 13 SDWIS / MT0003136 / 1025
2019 E. COLI MR 13 SDWIS / MT0003136 / 3014
2018 Lead and Copper Rule MR 7 SDWIS / MT0003136 / 5000
2017 Consumer Confidence Rule Other 10 SDWIS / MT0003136 / 7000
2017 Hexachlorocyclopentadiene MR 7 SDWIS / MT0003136 / 2042
2017 Endrin MR 4 SDWIS / MT0003136 / 2005
2017 BHC-GAMMA MR 4 SDWIS / MT0003136 / 2010
2017 Methoxychlor MR 4 SDWIS / MT0003136 / 2015
2017 Di(2-ethylhexyl) adipate MR 4 SDWIS / MT0003136 / 2035
2017 Simazine MR 4 SDWIS / MT0003136 / 2037
2017 Di(2-ethylhexyl) phthalate MR 4 SDWIS / MT0003136 / 2039
2017 Carbofuran MR 4 SDWIS / MT0003136 / 2046
2017 Atrazine MR 4 SDWIS / MT0003136 / 2050
2017 Heptachlor MR 4 SDWIS / MT0003136 / 2065

How West Yellowstone Town Of Compares

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

Metric West Yellowstone Town Of Montana avg Federal benchmark
Total violations 203 131.4 SDWA compliance, any non-zero count is a recorded breach
Health-based violations 4 11.5 Indicates a contaminant exceeded a federal MCL
PFAS detection None 62.2% EPA final rule (2024): PFOA/PFOS MCL = 4.0 ppt
Population served 9,899 492 Sizing context for compliance burden

Sources: EPA SDWIS and EPA National Primary Drinking Water Regulations (40 CFR Part 141). State averages computed across 2,263 regulated public water systems in Montana.

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 West Yellowstone Town Of water safe to drink?
West Yellowstone Town Of (PWS ID: MT0003136) has 203 recorded violations in the EPA SDWIS database. No PFAS contamination was detected in UCMR5 testing. This system serves 9,899 people using Groundwater sources.
How many people does West Yellowstone Town Of serve?
West Yellowstone Town Of serves 9,899 people in West Yellowstone, Montana. It is a Local-owned system using Groundwater water sources with 628 service connections.
What type of violations does West Yellowstone Town Of have?
West Yellowstone Town Of has 203 total violations: 4 health-based violations (MCL exceedances or treatment failures), 189 monitoring/reporting violations, and 3 treatment technique violations. Health-based violations indicate contaminant levels exceeded EPA safe limits.
Has PFAS been detected in West Yellowstone Town Of water?
No. West Yellowstone Town Of was tested for PFAS under the EPA's UCMR5 monitoring program and no PFAS contamination was detected.
What water source does West Yellowstone Town Of use?
West Yellowstone Town Of 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. PFAS data from EPA UCMR5 monitoring program (2023-2025). This data is provided for informational purposes only.
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.