Community Water System · PWS MT0000046
Ryan Dam Water System
Operator location Helena, Montana - smaller served population (≤ 999) at 230 people served; 189 SDWIS violations on record from groundwater sources.
- 230
- People served (this PWS)
- 189
- EPA violations (this PWS)
- 23
- Health-based (this PWS)
- Untested
- UCMR5 (this PWS)
Ryan Dam Water System standing, high SDWIS violation third
230 people served (SDWIS) - smaller served population (≤ 999). Corpus terciles use 29,740 systems serving 500+ (the sitemap cohort). Health-based share 12% is middle-third health share (≤ 23%).
The verdict
Ryan Dam Water System sits in the upper third of the sitemap cohort by violation count (189), so the tables below sample a dense compliance trail rather than a near-clean ledger. Population served is smaller (230; smaller served population (≤ 999)), so each violation row represents a compact service footprint. Health-based share is 12% (middle-third health share (≤ 23%)). No UCMR5 PFAS test appears for this system in this extract.
- 189
- Total EPA violations on record
- 12%
- Health-based (MCL / treatment failure)
- 230
- 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
- Community
- Owner Type
- Private
- Connections
- 14
- County
- Cascade
- School/Daycare
- No
- MCL Violations
- 20
- Monitoring Violations
- 160
- Treatment Tech Violations
- 3
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| Coliform (TCR) | MCL | 20 | 2008 |
| Coliform (TCR) | MR | 17 | 2008 |
| Lead and Copper Rule | MR | 13 | 2012 |
| Groundwater Rule | MR | 8 | 2019 |
| Consumer Confidence Rule | Other | 5 | 2019 |
| E. COLI | MR | 4 | 2023 |
| Nitrate-Nitrite | MR | 3 | 2000 |
| Endrin | MR | 3 | 1999 |
| Methoxychlor | MR | 3 | 1999 |
| Toxaphene | MR | 3 | 1999 |
| Dalapon | MR | 3 | 1999 |
| Endothall | MR | 3 | 1999 |
| Di(2-ethylhexyl) adipate | MR | 3 | 1999 |
| Simazine | MR | 3 | 1999 |
| Di(2-ethylhexyl) phthalate | MR | 3 | 1999 |
| Dinoseb | MR | 3 | 1999 |
| Aldicarb sulfoxide | MR | 3 | 1999 |
| Carbofuran | MR | 3 | 1999 |
| Atrazine | MR | 3 | 1999 |
| 2,3,7,8-TCDD | MR | 3 | 1999 |
| 2,4-D | MR | 3 | 1999 |
| 2,4,5-TP | MR | 3 | 1999 |
| Benzo(a)pyrene | MR | 3 | 1999 |
| Pentachlorophenol | MR | 3 | 1999 |
| Total Polychlorinated Biphenyls (PCB) | MR | 3 | 1999 |
| Chlordane | MR | 3 | 1999 |
| TTHM | MR | 3 | 2023 |
| Total Haloacetic Acids (HAA5) | MR | 3 | 2023 |
| Aldicarb sulfone | MR | 3 | 1999 |
| ETHYLENE DIBROMIDE | MR | 3 | 1999 |
Violation Count vs. the National Corpus
Ryan Dam Water System has 189 recorded EPA violations, 84% of the 29,740 public water systems serving 500+ people nationwide carry fewer, and 15% carry more. 12% of this system's own violations are health-based (23 of 189), 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)
189 Higher than most more violations than 84% 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 Ryan Dam Water System
EPA SDWIS lists 230 people served and 14 connections for this PWS, confirm the service-area footprint on the federal report before comparing to municipal census totals.
Sources: EPA SDWIS
Nationwide peers
189 violations · 230 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 Ryan Dam Water System
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.