PlainWater
States → Montana

Community Water System · PWS MT0000355

Westby Town Of

Westby, Montana 59275 - drinking water served from surface water sources to 172 people, tracked in EPA SDWIS and UCMR5.

172
People served
611
EPA violations
81
Health-based
Untested
UCMR5 result

The verdict

EPA records 611 drinking-water violations at Westby Town Of, 13% of them health-based - above the Montana per-system average.

611
Total EPA violations on record
13%
Health-based (MCL / treatment failure)
172
People served by this system
N/A
PFAS compounds detected (UCMR5)

Water Quality Snapshot: Westby Town Of

Westby Town Of is a local-owned community water system that delivers drinking water to 172 residents in Westby, Montana (Sheridan County) through 106 service connections. Its water is drawn from surface water sources. EPA's Safe Drinking Water Information System records 611 total violations for this system , of which 81 (13%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 524 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 Arsenic, recorded in 80 violations (MCL, health-based). 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%).

Westby Town Of's 611 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
172
Total Violations
611
Health-Based Violations
81
Water Source
Surface Water

System Details

System Type
Community
Owner Type
Local
Connections
106
County
Sheridan
School/Daycare
No
MCL Violations
81
Monitoring Violations
524
Treatment Tech Violations
0

Violation History

Contaminant violations recorded by EPA.

Contaminant Category Count Latest
Arsenic MCL 80 2015
Arsenic MR 27 2019
Toxaphene MR 9 2011
Di(2-ethylhexyl) phthalate MR 9 2011
Picloram MR 9 2011
Hexachlorocyclopentadiene MR 9 2011
Aldicarb sulfone MR 9 2011
Aldicarb MR 9 2011
Heptachlor MR 9 2011
2,4-D MR 9 2011
2,4,5-TP MR 9 2011
HEXACHLOROBENZENE MR 9 2011
Benzo(a)pyrene MR 9 2011
Pentachlorophenol MR 9 2011
Chlordane MR 9 2011
Di(2-ethylhexyl) adipate MR 9 2011
OXAMYL MR 9 2011
Carbofuran MR 9 2011
Atrazine MR 9 2011
Nitrate-Nitrite MR 9 2013
Endrin MR 9 2011
BHC-GAMMA MR 9 2011
Methoxychlor MR 9 2011
Dalapon MR 9 2011
Dinoseb MR 9 2011
LASSO MR 9 2011
Heptachlor epoxide MR 9 2011
Aldicarb sulfoxide MR 9 2011
Simazine MR 9 2011
1,2,4-Trichlorobenzene MR 7 2011

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 Westby 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 MT0000355 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 TTHM MR 3 SDWIS / MT0000355 / 2950
2022 Total Haloacetic Acids (HAA5) MR 3 SDWIS / MT0000355 / 2456
2019 Arsenic MR 27 SDWIS / MT0000355 / 1005
2015 Arsenic MCL 80 SDWIS / MT0000355 / 1005
2015 Lead and Copper Rule MR 5 SDWIS / MT0000355 / 5000
2013 Nitrate-Nitrite MR 9 SDWIS / MT0000355 / 1038
2013 E. COLI MR 2 SDWIS / MT0000355 / 3014
2011 Toxaphene MR 9 SDWIS / MT0000355 / 2020
2011 Di(2-ethylhexyl) phthalate MR 9 SDWIS / MT0000355 / 2039
2011 Picloram MR 9 SDWIS / MT0000355 / 2040
2011 Hexachlorocyclopentadiene MR 9 SDWIS / MT0000355 / 2042
2011 Aldicarb sulfone MR 9 SDWIS / MT0000355 / 2044
2011 Aldicarb MR 9 SDWIS / MT0000355 / 2047
2011 Heptachlor MR 9 SDWIS / MT0000355 / 2065
2011 2,4-D MR 9 SDWIS / MT0000355 / 2105

How Westby Town Of Compares

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

Metric Westby Town Of Montana avg Federal benchmark
Total violations 611 131.4 SDWA compliance, any non-zero count is a recorded breach
Health-based violations 81 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 172 492 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 Westby Town Of water safe to drink? ▼
Westby Town Of (PWS ID: MT0000355) has 611 recorded violations in the EPA SDWIS database. No PFAS contamination was detected in UCMR5 testing. This system serves 172 people using Surface Water sources.
How many people does Westby Town Of serve? ▼
Westby Town Of serves 172 people in Westby, Montana. It is a Local-owned system using Surface Water water sources with 106 service connections.
What type of violations does Westby Town Of have? ▼
Westby Town Of has 611 total violations: 81 health-based violations (MCL exceedances or treatment failures), 524 monitoring/reporting violations, and 0 treatment technique violations. Health-based violations indicate contaminant levels exceeded EPA safe limits.
Has PFAS been detected in Westby Town Of water? ▼
No PFAS testing data is available for Westby Town Of under the EPA's UCMR5 monitoring program.
What water source does Westby Town Of use? ▼
Westby Town Of uses Surface Water 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.