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Non-Transient Non-Community Water System · PWS MT0001085

Lone Rock School District No 13

Stevensville, Montana 59870 - drinking water served from groundwater sources to 280 people, tracked in EPA SDWIS and UCMR5.

280
People served
143
EPA violations
6
Health-based
Untested
UCMR5 result

The verdict

EPA records 143 drinking-water violations at Lone Rock School District No 13, 4% of them health-based - above the Montana per-system average.

143
Total EPA violations on record
4%
Health-based (MCL / treatment failure)
280
People served by this system
N/A
PFAS compounds detected (UCMR5)

Water Quality Snapshot: Lone Rock School District No 13

Lone Rock School District No 13 is a private-owned non-transient non-community water system that delivers drinking water to 280 residents in Stevensville, Montana (Ravalli County) through 2 service connections. Its water is drawn from groundwater sources. EPA's Safe Drinking Water Information System records 143 total violations for this system , of which 6 (4%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 134 monitoring and reporting violations are on file. The most recent violation on record dates to 2015.

The most frequently cited contaminant at this system is Coliform (TCR), recorded in 33 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%).

Lone Rock School District No 13's 143 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
280
Total Violations
143
Health-Based Violations
6
Water Source
Groundwater

System Details

System Type
Non-Transient Non-Community
Owner Type
Private
Connections
2
County
Ravalli
School/Daycare
Yes
MCL Violations
6
Monitoring Violations
134
Treatment Tech Violations
0

Violation History

Contaminant violations recorded by EPA.

Contaminant Category Count Latest
Coliform (TCR) MR 33 2015
Nitrate MR 9 1997
Coliform (TCR) MCL 6 2001
Lead and Copper Rule MR 5 1994
1,2,4-Trichlorobenzene MR 4 2002
Xylenes, Total MR 4 2002
DICHLOROMETHANE MR 4 2002
o-Dichlorobenzene MR 4 2002
trans-1,2-Dichloroethylene MR 4 2002
1,2-Dichloroethane MR 4 2002
1,1,1-Trichloroethane MR 4 2002
Carbon tetrachloride MR 4 2002
1,2-Dichloropropane MR 4 2002
Trichloroethylene MR 4 2002
1,1,2-Trichloroethane MR 4 2002
Tetrachloroethylene MR 4 2002
CHLOROBENZENE MR 4 2002
Benzene MR 4 2002
Toluene MR 4 2002
Ethylbenzene MR 4 2002
Styrene MR 4 2002
cis-1,2-Dichloroethylene MR 4 2002
Vinyl chloride MR 4 2002
1,1-Dichloroethylene MR 4 2002
p-Dichlorobenzene MR 4 2002
Nitrate-Nitrite MR 3 2006

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 Lone Rock School District No 13.

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 MT0001085 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
2015 Coliform (TCR) MR 33 SDWIS / MT0001085 / 3100
2006 Nitrate-Nitrite MR 3 SDWIS / MT0001085 / 1038
2002 1,2,4-Trichlorobenzene MR 4 SDWIS / MT0001085 / 2378
2002 Xylenes, Total MR 4 SDWIS / MT0001085 / 2955
2002 DICHLOROMETHANE MR 4 SDWIS / MT0001085 / 2964
2002 o-Dichlorobenzene MR 4 SDWIS / MT0001085 / 2968
2002 trans-1,2-Dichloroethylene MR 4 SDWIS / MT0001085 / 2979
2002 1,2-Dichloroethane MR 4 SDWIS / MT0001085 / 2980
2002 1,1,1-Trichloroethane MR 4 SDWIS / MT0001085 / 2981
2002 Carbon tetrachloride MR 4 SDWIS / MT0001085 / 2982
2002 1,2-Dichloropropane MR 4 SDWIS / MT0001085 / 2983
2002 Trichloroethylene MR 4 SDWIS / MT0001085 / 2984
2002 1,1,2-Trichloroethane MR 4 SDWIS / MT0001085 / 2985
2002 Tetrachloroethylene MR 4 SDWIS / MT0001085 / 2987
2002 CHLOROBENZENE MR 4 SDWIS / MT0001085 / 2989

How Lone Rock School District No 13 Compares

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

Metric Lone Rock School District No 13 Montana avg Federal benchmark
Total violations 143 131.4 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 280 492 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 Lone Rock School District No 13 water safe to drink? ▼
Lone Rock School District No 13 (PWS ID: MT0001085) has 143 recorded violations in the EPA SDWIS database. No PFAS contamination was detected in UCMR5 testing. This system serves 280 people using Groundwater sources.
How many people does Lone Rock School District No 13 serve? ▼
Lone Rock School District No 13 serves 280 people in Stevensville, Montana. It is a Private-owned system using Groundwater water sources with 2 service connections.
What type of violations does Lone Rock School District No 13 have? ▼
Lone Rock School District No 13 has 143 total violations: 6 health-based violations (MCL exceedances or treatment failures), 134 monitoring/reporting violations, and 0 treatment technique violations. Health-based violations indicate contaminant levels exceeded EPA safe limits.
Has PFAS been detected in Lone Rock School District No 13 water? ▼
No PFAS testing data is available for Lone Rock School District No 13 under the EPA's UCMR5 monitoring program.
What water source does Lone Rock School District No 13 use? ▼
Lone Rock School District No 13 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.