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Transient Non-Community Water System · PWS MT0000103

Yellowtail Dam Powerplant and Visitor Ce

Yellowtail, Montana 59035 - drinking water served from surface water sources to 48 people, tracked in EPA SDWIS and UCMR5.

48
People served
73
EPA violations
22
Health-based
Untested
UCMR5 result

The verdict

EPA records 73 drinking-water violations at Yellowtail Dam Powerplant and Visitor Ce, 30% of them health-based - below the Montana per-system average.

73
Total EPA violations on record
30%
Health-based (MCL / treatment failure)
48
People served by this system
N/A
PFAS compounds detected (UCMR5)

Water Quality Snapshot: Yellowtail Dam Powerplant and Visitor Ce

Yellowtail Dam Powerplant and Visitor Ce is a federal-owned transient non-community water system that delivers drinking water to 48 residents in Yellowtail, Montana (Big Horn County) through 3 service connections. Its water is drawn from surface water sources. EPA's Safe Drinking Water Information System records 73 total violations for this system , of which 22 (30%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 48 monitoring and reporting violations are on file. The most recent violation on record dates to 2022.

The most frequently cited contaminant at this system is Interim Enhanced Surface Water Treatment Rule, recorded in 17 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 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%).

Yellowtail Dam Powerplant and Visitor Ce's 73 violations sit below 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
48
Total Violations
73
Health-Based Violations
22
Water Source
Surface Water

System Details

System Type
Transient Non-Community
Owner Type
Federal
Connections
3
County
Big Horn
School/Daycare
No
MCL Violations
0
Monitoring Violations
48
Treatment Tech Violations
22

Violation History

Contaminant violations recorded by EPA.

Contaminant Category Count Latest
Interim Enhanced Surface Water Treatment Rule MR 17 2022
Nitrate-Nitrite MR 14 2017
Interim Enhanced Surface Water Treatment Rule TT 12 2019
Surface Water Treatment Rule TT 10 2010
Surface Water Treatment Rule MR 10 2006
Coliform (TCR) MR 7 2005

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 Yellowtail Dam Powerplant and Visitor Ce.

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 MT0000103 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
2022 Interim Enhanced Surface Water Treatment Rule MR 17 SDWIS / MT0000103 / 0300
2019 Interim Enhanced Surface Water Treatment Rule TT 12 SDWIS / MT0000103 / 0300
2017 Nitrate-Nitrite MR 14 SDWIS / MT0000103 / 1038
2010 Surface Water Treatment Rule TT 10 SDWIS / MT0000103 / 0200
2006 Surface Water Treatment Rule MR 10 SDWIS / MT0000103 / 0200
2005 Coliform (TCR) MR 7 SDWIS / MT0000103 / 3100

How Yellowtail Dam Powerplant and Visitor Ce Compares

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

Metric Yellowtail Dam Powerplant and Visitor Ce Montana avg Federal benchmark
Total violations 73 131.4 SDWA compliance, any non-zero count is a recorded breach
Health-based violations 22 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 48 492 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 Yellowtail Dam Powerplant and Visitor Ce water safe to drink? ▼
Yellowtail Dam Powerplant and Visitor Ce (PWS ID: MT0000103) has 73 recorded violations in the EPA SDWIS database. No PFAS contamination was detected in UCMR5 testing. This system serves 48 people using Surface Water sources.
How many people does Yellowtail Dam Powerplant and Visitor Ce serve? ▼
Yellowtail Dam Powerplant and Visitor Ce serves 48 people in Yellowtail, Montana. It is a Federal-owned system using Surface Water water sources with 3 service connections.
What type of violations does Yellowtail Dam Powerplant and Visitor Ce have? ▼
Yellowtail Dam Powerplant and Visitor Ce has 73 total violations: 22 health-based violations (MCL exceedances or treatment failures), 48 monitoring/reporting violations, and 22 treatment technique violations. Health-based violations indicate contaminant levels exceeded EPA safe limits.
Has PFAS been detected in Yellowtail Dam Powerplant and Visitor Ce water? ▼
No PFAS testing data is available for Yellowtail Dam Powerplant and Visitor Ce under the EPA's UCMR5 monitoring program.
What water source does Yellowtail Dam Powerplant and Visitor Ce use? ▼
Yellowtail Dam Powerplant and Visitor Ce uses Surface Water as its primary water source. It is classified as a Transient Non-Community Water System, serving transient populations.
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.