Community Water System · PWS MT0004462
Lower Pioneer Mountain Water System
Big Sky, Montana 59716 - drinking water served from groundwater sources to 350 people, tracked in EPA SDWIS and UCMR5.
- 350
- People served
- 168
- EPA violations
- 7
- Health-based
- Untested
- UCMR5 result
The verdict
EPA records 168 drinking-water violations at Lower Pioneer Mountain Water System, 4% of them health-based - above the Montana per-system average.
- 168
- Total EPA violations on record
- 4%
- Health-based (MCL / treatment failure)
- 350
- People served by this system
- N/A
- PFAS compounds detected (UCMR5)
Water Quality Snapshot: Lower Pioneer Mountain Water System
Lower Pioneer Mountain Water System is a private-owned community water system that delivers drinking water to 350 residents in Big Sky, Montana (Madison County) through 210 service connections. Its water is drawn from groundwater sources. EPA's Safe Drinking Water Information System records 168 total violations for this system , of which 7 (4%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 159 monitoring and reporting violations are on file. The most recent violation on record dates to 2020.
The most frequently cited contaminant at this system is Gross Alpha, Excl. Radon and U, recorded in 12 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%).
Lower Pioneer Mountain Water System's 168 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.
System Details
- System Type
- Community
- Owner Type
- Private
- Connections
- 210
- County
- Madison
- School/Daycare
- No
- MCL Violations
- 7
- Monitoring Violations
- 159
- Treatment Tech Violations
- 0
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| Gross Alpha, Excl. Radon and U | MR | 12 | 2008 |
| Lead and Copper Rule | MR | 7 | 2009 |
| DICHLOROMETHANE | MR | 6 | 2008 |
| p-Dichlorobenzene | MR | 6 | 2008 |
| Vinyl chloride | MR | 6 | 2008 |
| 1,1-Dichloroethylene | MR | 6 | 2008 |
| trans-1,2-Dichloroethylene | MR | 6 | 2008 |
| 1,2-Dichloroethane | MR | 6 | 2008 |
| Carbon tetrachloride | MR | 6 | 2008 |
| Trichloroethylene | MR | 6 | 2008 |
| 1,1,2-Trichloroethane | MR | 6 | 2008 |
| CHLOROBENZENE | MR | 6 | 2008 |
| Benzene | MR | 6 | 2008 |
| Ethylbenzene | MR | 6 | 2008 |
| Xylenes, Total | MR | 6 | 2008 |
| 1,2-Dichloropropane | MR | 6 | 2008 |
| Combined Radium (-226 and -228) | MR | 6 | 2008 |
| Tetrachloroethylene | MR | 6 | 2008 |
| Toluene | MR | 6 | 2008 |
| Styrene | MR | 6 | 2008 |
| 1,2,4-Trichlorobenzene | MR | 6 | 2008 |
| 1,1,1-Trichloroethane | MR | 6 | 2008 |
| cis-1,2-Dichloroethylene | MR | 6 | 2008 |
| o-Dichlorobenzene | MR | 6 | 2008 |
| Coliform (TCR) | MR | 5 | 2010 |
| Coliform (TCR) | MCL | 4 | 2015 |
| E. COLI | MR | 3 | 2010 |
| Revised Total Coliform Rule | MCL | 3 | 2020 |
| Consumer Confidence Rule | Other | 2 | 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 Lower Pioneer Mountain Water System.
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 MT0004462 on SDWISSource: EPA SDWIS Federal Reports Search
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 SDWISViolation 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 |
|---|---|---|---|---|
| 2020 | Revised Total Coliform Rule | MCL | 3 | SDWIS / MT0004462 / 8000 |
| 2020 | Consumer Confidence Rule | Other | 2 | SDWIS / MT0004462 / 7000 |
| 2015 | Coliform (TCR) | MCL | 4 | SDWIS / MT0004462 / 3100 |
| 2010 | Coliform (TCR) | MR | 5 | SDWIS / MT0004462 / 3100 |
| 2010 | E. COLI | MR | 3 | SDWIS / MT0004462 / 3014 |
| 2009 | Lead and Copper Rule | MR | 7 | SDWIS / MT0004462 / 5000 |
| 2008 | Gross Alpha, Excl. Radon and U | MR | 12 | SDWIS / MT0004462 / 4000 |
| 2008 | DICHLOROMETHANE | MR | 6 | SDWIS / MT0004462 / 2964 |
| 2008 | p-Dichlorobenzene | MR | 6 | SDWIS / MT0004462 / 2969 |
| 2008 | Vinyl chloride | MR | 6 | SDWIS / MT0004462 / 2976 |
| 2008 | 1,1-Dichloroethylene | MR | 6 | SDWIS / MT0004462 / 2977 |
| 2008 | trans-1,2-Dichloroethylene | MR | 6 | SDWIS / MT0004462 / 2979 |
| 2008 | 1,2-Dichloroethane | MR | 6 | SDWIS / MT0004462 / 2980 |
| 2008 | Carbon tetrachloride | MR | 6 | SDWIS / MT0004462 / 2982 |
| 2008 | Trichloroethylene | MR | 6 | SDWIS / MT0004462 / 2984 |
How Lower Pioneer Mountain Water System Compares
Cross-reference this system's record against state averages and the federal MCL framework for context.
| Metric | Lower Pioneer Mountain Water System | Montana avg | Federal benchmark |
|---|---|---|---|
| Total violations | 168 | 131.4 | SDWA compliance, any non-zero count is a recorded breach |
| Health-based violations | 7 | 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 | 350 | 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 Lower Pioneer Mountain Water System water safe to drink? ▼
How many people does Lower Pioneer Mountain Water System serve? ▼
What type of violations does Lower Pioneer Mountain Water System have? ▼
Has PFAS been detected in Lower Pioneer Mountain Water System water? ▼
What water source does Lower Pioneer Mountain Water System use? ▼
Where does this data come from? ▼
Read our methodology - how this data is sourced, computed, and verified.
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.