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Non-Transient Non-Community Water System · PWS MT0003790

Harrison School District No 23

Harrison, Montana 59735 - drinking water served from groundwater sources to 100 people, tracked in EPA SDWIS and UCMR5.

100
People served
1,139
EPA violations
1
Health-based
Untested
UCMR5 result

The verdict

EPA records 1,139 drinking-water violations at Harrison School District No 23 - above the Montana per-system average.

1,139
Total EPA violations on record
0%
Health-based (MCL / treatment failure)
100
People served by this system
N/A
PFAS compounds detected (UCMR5)

Water Quality Snapshot: Harrison School District No 23

Harrison School District No 23 is a local-owned non-transient non-community water system that delivers drinking water to 100 residents in Harrison, Montana (Madison County) through 1 service connections. Its water is drawn from groundwater sources. EPA's Safe Drinking Water Information System records 1,139 total violations for this system , of which 1 (0%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 1,138 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 Di(2-ethylhexyl) phthalate, recorded in 39 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%).

Harrison School District No 23's 1,139 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
100
Total Violations
1,139
Health-Based Violations
1
Water Source
Groundwater

System Details

System Type
Non-Transient Non-Community
Owner Type
Local
Connections
1
County
Madison
School/Daycare
Yes
MCL Violations
1
Monitoring Violations
1,138
Treatment Tech Violations
0

Violation History

Contaminant violations recorded by EPA.

Contaminant Category Count Latest
Di(2-ethylhexyl) phthalate MR 39 2020
Revised Total Coliform Rule MON 26 2025
Endrin MR 24 2020
Dalapon MR 24 2020
Di(2-ethylhexyl) adipate MR 24 2020
OXAMYL MR 24 2020
Picloram MR 24 2020
Dinoseb MR 24 2020
Hexachlorocyclopentadiene MR 24 2020
Heptachlor MR 24 2020
HEXACHLOROBENZENE MR 24 2020
Benzo(a)pyrene MR 24 2020
Pentachlorophenol MR 24 2020
Chlordane MR 24 2020
BHC-GAMMA MR 24 2020
Toxaphene MR 24 2020
Simazine MR 24 2020
Carbofuran MR 24 2020
Heptachlor epoxide MR 24 2020
2,4-D MR 24 2020
2,4,5-TP MR 24 2020
LASSO MR 24 2020
Methoxychlor MR 24 2020
Atrazine MR 24 2020
cis-1,2-Dichloroethylene MR 21 2020
Xylenes, Total MR 21 2020
Vinyl chloride MR 21 2020
1,1-Dichloroethylene MR 21 2020
trans-1,2-Dichloroethylene MR 21 2020
1,2-Dichloroethane MR 21 2020

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 Harrison School District No 23.

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 MT0003790 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 Revised Total Coliform Rule MON 26 SDWIS / MT0003790 / 8000
2024 Nitrate-Nitrite MR 3 SDWIS / MT0003790 / 1038
2022 Chlorine MR 3 SDWIS / MT0003790 / 0999
2021 Total Haloacetic Acids (HAA5) MR 2 SDWIS / MT0003790 / 2456
2021 TTHM MR 2 SDWIS / MT0003790 / 2950
2020 Di(2-ethylhexyl) phthalate MR 39 SDWIS / MT0003790 / 2039
2020 Endrin MR 24 SDWIS / MT0003790 / 2005
2020 Dalapon MR 24 SDWIS / MT0003790 / 2031
2020 Di(2-ethylhexyl) adipate MR 24 SDWIS / MT0003790 / 2035
2020 OXAMYL MR 24 SDWIS / MT0003790 / 2036
2020 Picloram MR 24 SDWIS / MT0003790 / 2040
2020 Dinoseb MR 24 SDWIS / MT0003790 / 2041
2020 Hexachlorocyclopentadiene MR 24 SDWIS / MT0003790 / 2042
2020 Heptachlor MR 24 SDWIS / MT0003790 / 2065
2020 HEXACHLOROBENZENE MR 24 SDWIS / MT0003790 / 2274

How Harrison School District No 23 Compares

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

Metric Harrison School District No 23 Montana avg Federal benchmark
Total violations 1,139 131.4 SDWA compliance, any non-zero count is a recorded breach
Health-based violations 1 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 100 492 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 Harrison School District No 23 water safe to drink? ▼
Harrison School District No 23 (PWS ID: MT0003790) has 1139 recorded violations in the EPA SDWIS database. No PFAS contamination was detected in UCMR5 testing. This system serves 100 people using Groundwater sources.
How many people does Harrison School District No 23 serve? ▼
Harrison School District No 23 serves 100 people in Harrison, Montana. It is a Local-owned system using Groundwater water sources with 1 service connections.
What type of violations does Harrison School District No 23 have? ▼
Harrison School District No 23 has 1,139 total violations: 1 health-based violations (MCL exceedances or treatment failures), 1,138 monitoring/reporting violations, and 0 treatment technique violations. Health-based violations indicate contaminant levels exceeded EPA safe limits.
Has PFAS been detected in Harrison School District No 23 water? ▼
No PFAS testing data is available for Harrison School District No 23 under the EPA's UCMR5 monitoring program.
What water source does Harrison School District No 23 use? ▼
Harrison School District No 23 uses Groundwater as its primary water source. It is classified as a Non-Transient Non-Community Water System, serving the same people for at least 6 months per year.
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.