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Community Water System · PWS MT0000240

Harlowton City Of

Harlowton, Montana 59036 - drinking water served from groundwater sources to 1,050 people, tracked in EPA SDWIS and UCMR5.

1,050
People served
118
EPA violations
6
Health-based
Untested
UCMR5 result

The verdict

EPA records 118 drinking-water violations at Harlowton City Of, 5% of them health-based - below the Montana per-system average.

118
Total EPA violations on record
5%
Health-based (MCL / treatment failure)
1,050
People served by this system
N/A
PFAS compounds detected (UCMR5)

Water Quality Snapshot: Harlowton City Of

Harlowton City Of is a local-owned community water system that delivers drinking water to 1,050 residents in Harlowton, Montana (Wheatland County) through 573 service connections. Its water is drawn from groundwater sources. EPA's Safe Drinking Water Information System records 118 total violations for this system , of which 6 (5%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 94 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 Lead and Copper Rule, recorded in 60 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%).

Harlowton City Of's 118 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
1,050
Total Violations
118
Health-Based Violations
6
Water Source
Groundwater

System Details

System Type
Community
Owner Type
Local
Connections
573
County
Wheatland
School/Daycare
No
MCL Violations
0
Monitoring Violations
94
Treatment Tech Violations
6

Violation History

Contaminant violations recorded by EPA.

Contaminant Category Count Latest
Lead and Copper Rule MR 60 2006
Consumer Confidence Rule Other 17 2025
Nitrate-Nitrite MR 9 2009
Arsenic MR 8 2008
Lead and Copper Rule TT 6 1999
Revised Total Coliform Rule MON 4 2024
Total Haloacetic Acids (HAA5) MR 3 2004
TTHM MR 3 2004
Mercury MR 1 1984
Nitrate MR 1 1984
Cadmium MR 1 1984
Selenium MR 1 1984
Barium MR 1 1984
Fluoride MR 1 1984
Chromium MR 1 1984

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 Harlowton City 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 MT0000240 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
2025 Consumer Confidence Rule Other 17 SDWIS / MT0000240 / 7000
2024 Revised Total Coliform Rule MON 4 SDWIS / MT0000240 / 8000
2009 Nitrate-Nitrite MR 9 SDWIS / MT0000240 / 1038
2008 Arsenic MR 8 SDWIS / MT0000240 / 1005
2006 Lead and Copper Rule MR 60 SDWIS / MT0000240 / 5000
2004 Total Haloacetic Acids (HAA5) MR 3 SDWIS / MT0000240 / 2456
2004 TTHM MR 3 SDWIS / MT0000240 / 2950
1999 Lead and Copper Rule TT 6 SDWIS / MT0000240 / 5000
1984 Mercury MR 1 SDWIS / MT0000240 / 1035
1984 Nitrate MR 1 SDWIS / MT0000240 / 1040
1984 Cadmium MR 1 SDWIS / MT0000240 / 1015
1984 Selenium MR 1 SDWIS / MT0000240 / 1045
1984 Barium MR 1 SDWIS / MT0000240 / 1010
1984 Fluoride MR 1 SDWIS / MT0000240 / 1025
1984 Chromium MR 1 SDWIS / MT0000240 / 1020

How Harlowton City Of Compares

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

Metric Harlowton City Of Montana avg Federal benchmark
Total violations 118 131.4 SDWA compliance, any non-zero count is a recorded breach
Health-based violations 6 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 1,050 492 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 Harlowton City Of water safe to drink? ▼
Harlowton City Of (PWS ID: MT0000240) has 118 recorded violations in the EPA SDWIS database. No PFAS contamination was detected in UCMR5 testing. This system serves 1,050 people using Groundwater sources.
How many people does Harlowton City Of serve? ▼
Harlowton City Of serves 1,050 people in Harlowton, Montana. It is a Local-owned system using Groundwater water sources with 573 service connections.
What type of violations does Harlowton City Of have? ▼
Harlowton City Of has 118 total violations: 6 health-based violations (MCL exceedances or treatment failures), 94 monitoring/reporting violations, and 6 treatment technique violations. Health-based violations indicate contaminant levels exceeded EPA safe limits.
Has PFAS been detected in Harlowton City Of water? ▼
No PFAS testing data is available for Harlowton City Of under the EPA's UCMR5 monitoring program.
What water source does Harlowton City Of use? ▼
Harlowton City 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. 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.