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States → Montana

Non-Transient Non-Community Water System · PWS MT0003089

Rau School District No 21

Sidney, Montana 59270 - drinking water served from groundwater sources to 80 people, tracked in EPA SDWIS and UCMR5.

80
People served
1,091
EPA violations
24
Health-based
Untested
UCMR5 result

The verdict

EPA records 1,091 drinking-water violations at Rau School District No 21, 2% of them health-based - above the Montana per-system average.

1,091
Total EPA violations on record
2%
Health-based (MCL / treatment failure)
80
People served by this system
N/A
PFAS compounds detected (UCMR5)

Water Quality Snapshot: Rau School District No 21

Rau School District No 21 is a local-owned non-transient non-community water system that delivers drinking water to 80 residents in Sidney, Montana (Richland County) through 1 service connections. Its water is drawn from groundwater sources. EPA's Safe Drinking Water Information System records 1,091 total violations for this system , of which 24 (2%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 1,014 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 170 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%).

Rau School District No 21's 1,091 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
80
Total Violations
1,091
Health-Based Violations
24
Water Source
Groundwater

System Details

System Type
Non-Transient Non-Community
Owner Type
Local
Connections
1
County
Richland
School/Daycare
Yes
MCL Violations
12
Monitoring Violations
1,014
Treatment Tech Violations
12

Violation History

Contaminant violations recorded by EPA.

Contaminant Category Count Latest
Lead and Copper Rule MR 170 2025
Coliform (TCR) MR 64 2015
Endrin MR 25 2020
Dinoseb MR 25 2020
BHC-GAMMA MR 25 2020
Heptachlor MR 25 2020
Toxaphene MR 25 2020
Simazine MR 25 2020
Chlordane MR 25 2020
2,4,5-TP MR 25 2020
Heptachlor epoxide MR 25 2020
Pentachlorophenol MR 25 2020
Hexachlorocyclopentadiene MR 25 2020
Methoxychlor MR 25 2020
LASSO MR 25 2020
HEXACHLOROBENZENE MR 25 2020
Picloram MR 25 2020
Benzo(a)pyrene MR 25 2020
Dalapon MR 25 2020
Di(2-ethylhexyl) adipate MR 25 2020
Atrazine MR 25 2020
2,4-D MR 25 2020
OXAMYL MR 22 2020
Carbofuran MR 22 2020
Di(2-ethylhexyl) phthalate MR 22 2020
Arsenic MR 21 2009
Revised Total Coliform Rule MON 21 2022
Nitrate-Nitrite MR 16 2017
Revised Total Coliform Rule RPT 15 2021
Lead and Copper Rule TT 12 2017

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 Rau School District No 21.

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 MT0003089 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 Lead and Copper Rule MR 170 SDWIS / MT0003089 / 5000
2022 Revised Total Coliform Rule MON 21 SDWIS / MT0003089 / 8000
2021 Revised Total Coliform Rule RPT 15 SDWIS / MT0003089 / 8000
2021 Total Haloacetic Acids (HAA5) MR 9 SDWIS / MT0003089 / 2456
2021 TTHM MR 9 SDWIS / MT0003089 / 2950
2020 Endrin MR 25 SDWIS / MT0003089 / 2005
2020 Dinoseb MR 25 SDWIS / MT0003089 / 2041
2020 BHC-GAMMA MR 25 SDWIS / MT0003089 / 2010
2020 Heptachlor MR 25 SDWIS / MT0003089 / 2065
2020 Toxaphene MR 25 SDWIS / MT0003089 / 2020
2020 Simazine MR 25 SDWIS / MT0003089 / 2037
2020 Chlordane MR 25 SDWIS / MT0003089 / 2959
2020 2,4,5-TP MR 25 SDWIS / MT0003089 / 2110
2020 Heptachlor epoxide MR 25 SDWIS / MT0003089 / 2067
2020 Pentachlorophenol MR 25 SDWIS / MT0003089 / 2326

How Rau School District No 21 Compares

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

Metric Rau School District No 21 Montana avg Federal benchmark
Total violations 1,091 131.4 SDWA compliance, any non-zero count is a recorded breach
Health-based violations 24 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 80 492 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 Rau School District No 21 water safe to drink? ▼
Rau School District No 21 (PWS ID: MT0003089) has 1091 recorded violations in the EPA SDWIS database. No PFAS contamination was detected in UCMR5 testing. This system serves 80 people using Groundwater sources.
How many people does Rau School District No 21 serve? ▼
Rau School District No 21 serves 80 people in Sidney, Montana. It is a Local-owned system using Groundwater water sources with 1 service connections.
What type of violations does Rau School District No 21 have? ▼
Rau School District No 21 has 1,091 total violations: 24 health-based violations (MCL exceedances or treatment failures), 1,014 monitoring/reporting violations, and 12 treatment technique violations. Health-based violations indicate contaminant levels exceeded EPA safe limits.
Has PFAS been detected in Rau School District No 21 water? ▼
No PFAS testing data is available for Rau School District No 21 under the EPA's UCMR5 monitoring program.
What water source does Rau School District No 21 use? ▼
Rau School District No 21 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.