Community Water System · PWS SD4600112
Tri-County Rural Water System
Operator location Eagle Butte, South Dakota - 30% of 172 violations are health-based (upper-third health share (> 23%)); surface water source; 2,190 served per SDWIS.
- 2,190
- People served (this PWS)
- 172
- EPA violations (this PWS)
- 51
- Health-based (this PWS)
- No PFAS
- UCMR5 (this PWS)
Tri-County Rural Water System standing, high SDWIS violation third
30% of 172 recorded violations are health-based - upper-third health share (> 23%). Corpus terciles use 29,740 systems serving 500+ (the sitemap cohort). Health-based share 30% is upper-third health share (> 23%). UCMR5: UCMR5 tested, none detected. Population rank #12,916 of 29,740 among systems serving 500+.
The verdict
Tri-County Rural Water System sits in the upper third of the sitemap cohort by violation count (172), so the tables below sample a dense compliance trail rather than a near-clean ledger. Population served is mid-pack at 2,190 (mid served population (≤ 3,309)). Health-based share is 30% - most of this ledger is MCL or treatment-technique exceedance. UCMR5 tested this system and reported no PFAS above the minimum reporting level.
- #12,916 of 29,740
- Population · /systems
- #65 of 171
- Population · SD
- 172
- Total EPA violations on record
- 30%
- Health-based (MCL / treatment failure)
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
- 876
- County
- Dewey
- School/Daycare
- No
- MCL Violations
- 38
- Monitoring Violations
- 98
- Treatment Tech Violations
- 13
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| TTHM | MCL | 23 | 2006 |
| Total Haloacetic Acids (HAA5) | MCL | 15 | 2005 |
| Interim Enhanced Surface Water Treatment Rule | TT | 13 | 2009 |
| 1,2-DIBROMO-3-CHLOROPROPANE | MR | 6 | 2002 |
| Endothall | MR | 6 | 2002 |
| Public Notice | Other | 6 | 2006 |
| ETHYLENE DIBROMIDE | MR | 6 | 2002 |
| Glyphosate | MR | 6 | 2002 |
| Total Haloacetic Acids (HAA5) | MR | 4 | 2005 |
| Coliform (TCR) | MR | 4 | 1998 |
| TTHM | MR | 4 | 2005 |
| Consumer Confidence Rule | Other | 4 | 2005 |
| Lead and Copper Rule | MR | 3 | 1996 |
| Revised Total Coliform Rule | MON | 3 | 2022 |
| LASSO | MR | 2 | 2002 |
| Atrazine | MR | 2 | 2002 |
| Total Polychlorinated Biphenyls (PCB) | MR | 2 | 2002 |
| Hexachlorocyclopentadiene | MR | 2 | 2002 |
| HEXACHLOROBENZENE | MR | 2 | 2002 |
| Chlordane | MR | 2 | 2002 |
| Carbofuran | MR | 2 | 2002 |
| OXAMYL | MR | 2 | 2002 |
| Dinoseb | MR | 2 | 2002 |
| Pentachlorophenol | MR | 2 | 2002 |
| 2,4-D | MR | 2 | 2002 |
| Chlorine | MR | 2 | 2022 |
| Nitrate | MR | 2 | 1993 |
| Diquat | MR | 2 | 2002 |
| Picloram | MR | 2 | 2002 |
| Di(2-ethylhexyl) phthalate | MR | 2 | 2002 |
Violation Count vs. the National Corpus
Tri-County Rural Water System has 172 recorded EPA violations, 83% of the 29,740 public water systems serving 500+ people nationwide carry fewer, and 17% carry more. 30% of this system's own violations are health-based (51 of 172), and it ranks #12,916 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)
172 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
PFAS Testing Results (UCMR5)
Results from EPA's Fifth Unregulated Contaminant Monitoring Rule. 0 of 87 samples detected PFAS.
| Contaminant | Date | Result | MRL | Status |
|---|---|---|---|---|
| PFDoA | 7/15/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFMPA | 7/15/2025 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFOA | 7/15/2025 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFHpS | 7/15/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFPeS | 7/15/2025 | <4.00 ppt | 4.00 ppt | Not Detected |
| NFDHA | 7/15/2025 | <20.00 ppt | 20.00 ppt | Not Detected |
| PFEESA | 7/15/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFPeA | 7/15/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| 4:2 FTS | 7/15/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| 6:2 FTS | 7/15/2025 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFBA | 7/15/2025 | <5.00 ppt | 5.00 ppt | Not Detected |
| HFPO-DA | 7/15/2025 | <5.00 ppt | 5.00 ppt | Not Detected |
| ADONA | 7/15/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| 9Cl-PF3ONS | 7/15/2025 | <2.00 ppt | 2.00 ppt | Not Detected |
| PFBS | 7/15/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFTA | 7/15/2025 | <8.00 ppt | 8.00 ppt | Not Detected |
| PFMBA | 7/15/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| 11Cl-PF3OUdS | 7/15/2025 | <5.00 ppt | 5.00 ppt | Not Detected |
| NEtFOSAA | 7/15/2025 | <5.00 ppt | 5.00 ppt | Not Detected |
| 8:2 FTS | 7/15/2025 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFTrDA | 7/15/2025 | <7.00 ppt | 7.00 ppt | Not Detected |
| PFHpA | 7/15/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHxS | 7/15/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFNA | 7/15/2025 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFOS | 7/15/2025 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFDA | 7/15/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHxA | 7/15/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFUnA | 7/15/2025 | <2.00 ppt | 2.00 ppt | Not Detected |
| NMeFOSAA | 7/15/2025 | <6.00 ppt | 6.00 ppt | Not Detected |
| PFDA | 4/14/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFBA | 4/14/2025 | <5.00 ppt | 5.00 ppt | Not Detected |
| HFPO-DA | 4/14/2025 | <5.00 ppt | 5.00 ppt | Not Detected |
| ADONA | 4/14/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| 9Cl-PF3ONS | 4/14/2025 | <2.00 ppt | 2.00 ppt | Not Detected |
| 11Cl-PF3OUdS | 4/14/2025 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFUnA | 4/14/2025 | <2.00 ppt | 2.00 ppt | Not Detected |
| PFHpS | 4/14/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFDoA | 4/14/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| 4:2 FTS | 4/14/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFOA | 4/14/2025 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFOS | 4/14/2025 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFNA | 4/14/2025 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFHxA | 4/14/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFTrDA | 4/14/2025 | <7.00 ppt | 7.00 ppt | Not Detected |
| PFPeS | 4/14/2025 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFHxS | 4/14/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| NFDHA | 4/14/2025 | <20.00 ppt | 20.00 ppt | Not Detected |
| PFEESA | 4/14/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFMBA | 4/14/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHpA | 4/14/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
Health-based violations on Tri-County Rural Water System
51 health-based rows in the tables above map to MCL or treatment-technique exceedances, verify each contaminant code on the federal SDWIS report for SD4600112.
Sources: EPA SDWIS
Nationwide peers
172 violations · 2,190 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 near this population served
Nearest cross-state systems by EPA SDWIS population_served (same 500+ sitemap gate).
What to do with Tri-County Rural Water System
Use this system's EPA-reported record as a starting filter, not a final verdict.
- See how every tracked system in South Dakota compares on the same EPA violation measures. South Dakota 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.