Non-Transient Non-Community Water System · PWS MT0003089
Rau School District No 21
Operator location Sidney, Montana - smaller served population (≤ 999) at 80 people served; 1,091 SDWIS violations on record from groundwater sources.
- 80
- People served (this PWS)
- 1,091
- EPA violations (this PWS)
- 24
- Health-based (this PWS)
- Untested
- UCMR5 (this PWS)
Rau School District No 21 standing, high SDWIS violation third
80 people served (SDWIS) - smaller served population (≤ 999). Corpus terciles use 29,740 systems serving 500+ (the sitemap cohort). Health-based share 2% is middle-third health share (≤ 23%).
The verdict
Rau School District No 21 sits in the upper third of the sitemap cohort by violation count (1,091), so the tables below sample a dense compliance trail rather than a near-clean ledger. Population served is smaller (80; smaller served population (≤ 999)), so each violation row represents a compact service footprint. Health-based share is 2% (middle-third health share (≤ 23%)). No UCMR5 PFAS test appears for this system in this extract.
- 1,091
- Total EPA violations on record
- 2%
- Health-based (MCL / treatment failure)
- 80
- People served by this PWS (SDWIS)
- N/A
- PFAS compounds detected (UCMR5)
Population ordinals match the sitemap cohort (systems serving 500+, population_served DESC). See methodology · corpus placement.
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 |
Violation Count vs. the National Corpus
Rau School District No 21 has 1,091 recorded EPA violations, 99% of the 29,740 public water systems serving 500+ people nationwide carry fewer, and 1% carry more. 2% of this system's own violations are health-based (24 of 1,091), and it ranks unranked by population served among that same cohort.
EPA violations vs. the national water-system corpus
Public water systems serving 500+ people (EPA SDWIS)
1,091 Higher than most more violations than 99% 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
Population served record for Rau School District No 21
EPA SDWIS lists 80 people served and 1 connections for this PWS, confirm the service-area footprint on the federal report before comparing to municipal census totals.
Sources: EPA SDWIS
Nationwide peers
1,091 violations · 80 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.
What to do with Rau School District No 21
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.