Community Water System · PWS MT0004082
River Rock County Water and Sewer Dist
Operator location Belgrade, Montana - larger served population (> 3,309) at 4,200 people served; 176 SDWIS violations on record from groundwater sources.
- 4,200
- People served (this PWS) Larger third of systems
- 176
- EPA violations (this PWS) Upper third of systems
- 28
- Health-based (this PWS) Middle third by health-based share
- No PFAS
- UCMR5 (this PWS) Tested, none detected
River Rock County Water and Sewer Dist standing, high SDWIS violation third
4,200 people served (SDWIS) - larger served population (> 3,309). Corpus terciles use 29,740 systems serving 500+ (the sitemap cohort). Health-based share 16% is middle-third health share (≤ 23%). UCMR5: UCMR5 tested, none detected. Population rank #8,591 of 29,740 among systems serving 500+.
The verdict
River Rock County Water and Sewer Dist sits in the upper third of the sitemap cohort by violation count (176), so the tables below sample a dense compliance trail rather than a near-clean ledger. Population served is large (4,200; larger served population (> 3,309)), so household exposure scale sits behind the violation mix. Health-based share is 16% (middle-third health share (≤ 23%)). UCMR5 tested this system and reported no PFAS above the minimum reporting level.
- #8,591 of 29,740
- Population · /systems
- #33 of 283
- Population · MT
- 176
- Total EPA violations on record
- 16%
- Health-based (MCL / treatment failure)
Population ordinals match the sitemap cohort (systems serving 500+, population_served DESC). See methodology · corpus placement.
Based on EPA SDWIS violation history and UCMR5 PFAS testing only, not water taste, odor, infrastructure age, or contaminants outside the federally tracked set.
System Details
- System Type
- Community
- Owner Type
- Private
- Connections
- 1,204
- County
- Gallatin
- School/Daycare
- No
- MCL Violations
- 28
- Monitoring Violations
- 136
- Treatment Tech Violations
- 0
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| Lead and Copper Rule | MR | 59 | 2024 |
| Coliform (TCR) | MCL | 28 | 2008 |
| TTHM | MR | 18 | 2024 |
| Total Haloacetic Acids (HAA5) | MR | 18 | 2024 |
| Consumer Confidence Rule | Other | 10 | 2015 |
| Nitrate-Nitrite | MR | 9 | 2021 |
| Asbestos | MR | 4 | 2020 |
| Coliform (TCR) | MR | 4 | 2002 |
| Diquat | MR | 3 | 2020 |
| Endothall | MR | 3 | 2020 |
| ETHYLENE DIBROMIDE | MR | 3 | 2020 |
| 1,2-DIBROMO-3-CHLOROPROPANE | MR | 3 | 2020 |
| Antimony, Total | MR | 3 | 2017 |
| CYANIDE | MR | 3 | 2020 |
| Glyphosate | MR | 3 | 2020 |
| Total Polychlorinated Biphenyls (PCB) | MR | 3 | 2020 |
Violation Count vs. the National Corpus
River Rock County Water and Sewer Dist has 176 recorded EPA violations, 83% of the 29,740 public water systems serving 500+ people nationwide carry fewer, and 16% carry more. 16% of this system's own violations are health-based (28 of 176), and it ranks #8,591 of 29,740 by population served among that same cohort.
EPA violations vs. the national water-system corpus
Public water systems serving 500+ people (EPA SDWIS)
176 Higher than most more violations than 83% of 29,740 water systems
the national water-system corpus, bucketed by value
Each bar is a band; taller bars hold more water systems. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count and share, and where it sits relative to this entry.
Source EPA SDWIS · 2026-05-15
How many violations vs. how serious, among peer systems
River Rock County Water and Sewer Dist plotted against 29 peer public water systems (500+ people served), by total violation count (x) and the share of those violations that are health-based (y). The crosshair sits at this sample's own median on each axis. A high violation count does not automatically mean a serious record: most monitoring and reporting violations are minor, not health-based.
Violation volume vs. health-based share
PFAS Testing Results (UCMR5)
Results from EPA's Fifth Unregulated Contaminant Monitoring Rule. 0 of 58 samples detected PFAS.
| Contaminant | Date | Result | MRL | Status |
|---|---|---|---|---|
| 4:2 FTS | 5/15/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| ADONA | 5/15/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFTrDA | 5/15/2024 | <7.00 ppt | 7.00 ppt | Not Detected |
| NEtFOSAA | 5/15/2024 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFHpS | 5/15/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFPeS | 5/15/2024 | <4.00 ppt | 4.00 ppt | Not Detected |
| NFDHA | 5/15/2024 | <20.00 ppt | 20.00 ppt | Not Detected |
| PFEESA | 5/15/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFMBA | 5/15/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFPeA | 5/15/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFMPA | 5/15/2024 | <4.00 ppt | 4.00 ppt | Not Detected |
| 8:2 FTS | 5/15/2024 | <5.00 ppt | 5.00 ppt | Not Detected |
| 6:2 FTS | 5/15/2024 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFBA | 5/15/2024 | <5.00 ppt | 5.00 ppt | Not Detected |
| HFPO-DA | 5/15/2024 | <5.00 ppt | 5.00 ppt | Not Detected |
| NMeFOSAA | 5/15/2024 | <6.00 ppt | 6.00 ppt | Not Detected |
| 9Cl-PF3ONS | 5/15/2024 | <2.00 ppt | 2.00 ppt | Not Detected |
| 11Cl-PF3OUdS | 5/15/2024 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFUnA | 5/15/2024 | <2.00 ppt | 2.00 ppt | Not Detected |
| PFHxA | 5/15/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFDoA | 5/15/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFDA | 5/15/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFOA | 5/15/2024 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFOS | 5/15/2024 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFNA | 5/15/2024 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFHxS | 5/15/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHpA | 5/15/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFBS | 5/15/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFTA | 5/15/2024 | <8.00 ppt | 8.00 ppt | Not Detected |
| PFBS | 11/8/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHxA | 11/8/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFDoA | 11/8/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFDA | 11/8/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFOA | 11/8/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFOS | 11/8/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFNA | 11/8/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFHpA | 11/8/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| 11Cl-PF3OUdS | 11/8/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFTrDA | 11/8/2023 | <7.00 ppt | 7.00 ppt | Not Detected |
| NEtFOSAA | 11/8/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFHxS | 11/8/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| 8:2 FTS | 11/8/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFPeS | 11/8/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFHpS | 11/8/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFEESA | 11/8/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| NMeFOSAA | 11/8/2023 | <6.00 ppt | 6.00 ppt | Not Detected |
| PFMBA | 11/8/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFUnA | 11/8/2023 | <2.00 ppt | 2.00 ppt | Not Detected |
| PFMPA | 11/8/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFTA | 11/8/2023 | <8.00 ppt | 8.00 ppt | Not Detected |
Population served record for River Rock County Water and Sewer Dist
EPA SDWIS lists 4,200 people served and 1,204 connections for this PWS, confirm the service-area footprint on the federal report before comparing to municipal census totals.
Sources: EPA SDWIS
Nationwide peers
176 violations · 4,200 served: nearest cross-state SDWIS matches.
Cross-state systems with comparable violation load
Nearest cross-state community systems (500+ served) by total SDWIS violations on record.
Cross-state systems with similar served population
Nearest cross-state systems by EPA SDWIS population_served (same 500+ sitemap gate).
What to do with River Rock County Water and Sewer Dist
Use this system's EPA-reported record as a starting filter, not a final verdict.
- See how every tracked system in Montana compares on the same EPA violation measures. Montana systems
- Check whether PFAS was detected at this system under UCMR5 testing. PFAS guide
- Find and compare another public water system by name or PWSID. Search systems
EPA SDWIS and UCMR5 figures are informational only, not a substitute for a certified lab test of your own tap water.
Every figure on PlainWater is rendered directly from EPA SDWIS drinking-water data, no number is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.