Community Water System · PWS 055294502
Prairie Island
Operator location Welch, EPA Region 5 — Tribal Water Systems - 0% of 188 violations are health-based (lower-third health share (≤ 1%)); groundwater source; 6,699 served per SDWIS.
- 6,699
- People served (this PWS)
- 188
- EPA violations (this PWS)
- 0
- Health-based (this PWS)
- No PFAS
- UCMR5 (this PWS)
Prairie Island standing, high SDWIS violation third
0% of 188 recorded violations are health-based - lower-third health share (≤ 1%). Corpus terciles use 29,740 systems serving 500+ (the sitemap cohort). Health-based share 0% is lower-third health share (≤ 1%). UCMR5: UCMR5 tested, none detected. Population rank #6,320 of 29,740 among systems serving 500+.
The verdict
Prairie Island sits in the upper third of the sitemap cohort by violation count (188), so the tables below sample a dense compliance trail rather than a near-clean ledger. Population served is large (6,699; larger served population (> 3,309)), so household exposure scale sits behind the violation mix. Health-based share is only 0% - almost all of this trail is monitoring or reporting. UCMR5 tested this system and reported no PFAS above the minimum reporting level.
- #6,320 of 29,740
- Population · /systems
- #4 of 46
- Population · 05
- 188
- Total EPA violations on record
- 0%
- 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
- Native American
- Connections
- 110
- School/Daycare
- No
- MCL Violations
- 0
- Monitoring Violations
- 170
- Treatment Tech Violations
- 0
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| Coliform (TCR) | MR | 17 | 1994 |
| Nitrate | MR | 8 | 2023 |
| Lead and Copper Rule | MR | 7 | 2023 |
| Heptachlor | MR | 4 | 2017 |
| Barium | MR | 3 | 2017 |
| Cadmium | MR | 3 | 2017 |
| CYANIDE | MR | 3 | 2017 |
| Fluoride | MR | 3 | 2017 |
| Mercury | MR | 3 | 2017 |
| Nickel | MR | 3 | 2017 |
| Antimony, Total | MR | 3 | 2017 |
| o-Dichlorobenzene | MR | 3 | 1996 |
| 1,1-Dichloroethylene | MR | 3 | 1996 |
| cis-1,2-Dichloroethylene | MR | 3 | 1996 |
| trans-1,2-Dichloroethylene | MR | 3 | 1996 |
| DICHLOROMETHANE | MR | 3 | 1996 |
| 1,2-Dichloropropane | MR | 3 | 1996 |
| Ethylbenzene | MR | 3 | 1996 |
| Styrene | MR | 3 | 1996 |
| Toluene | MR | 3 | 1996 |
| 1,2,4-Trichlorobenzene | MR | 3 | 1996 |
| 1,1,1-Trichloroethane | MR | 3 | 1996 |
| 1,1,2-Trichloroethane | MR | 3 | 1996 |
| Trichloroethylene | MR | 3 | 1996 |
| Vinyl chloride | MR | 3 | 1996 |
| Carbon tetrachloride | MR | 3 | 1996 |
| p-Dichlorobenzene | MR | 3 | 1996 |
| Xylenes, Total | MR | 3 | 1996 |
| Tetrachloroethylene | MR | 3 | 1996 |
| LEAD AND COPPER RULE REVISIONS | RPT | 3 | 2024 |
Violation Count vs. the National Corpus
Prairie Island has 188 recorded EPA violations, 84% of the 29,740 public water systems serving 500+ people nationwide carry fewer, and 16% carry more. 0% of this system's own violations are health-based (0 of 188), and it ranks #6,320 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)
188 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
PFAS Testing Results (UCMR5)
Results from EPA's Fifth Unregulated Contaminant Monitoring Rule. 0 of 58 samples detected PFAS.
| Contaminant | Date | Result | MRL | Status |
|---|---|---|---|---|
| HFPO-DA | 6/5/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFHxA | 6/5/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| 9Cl-PF3ONS | 6/5/2023 | <2.00 ppt | 2.00 ppt | Not Detected |
| 11Cl-PF3OUdS | 6/5/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFUnA | 6/5/2023 | <2.00 ppt | 2.00 ppt | Not Detected |
| ADONA | 6/5/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFDoA | 6/5/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFDA | 6/5/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFOA | 6/5/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFOS | 6/5/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFBS | 6/5/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFBA | 6/5/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| NMeFOSAA | 6/5/2023 | <6.00 ppt | 6.00 ppt | Not Detected |
| PFNA | 6/5/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| 6:2 FTS | 6/5/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| 4:2 FTS | 6/5/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| 8:2 FTS | 6/5/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFMPA | 6/5/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFPeA | 6/5/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFMBA | 6/5/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFEESA | 6/5/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| NFDHA | 6/5/2023 | <20.00 ppt | 20.00 ppt | Not Detected |
| PFPeS | 6/5/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFHpS | 6/5/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFTA | 6/5/2023 | <8.00 ppt | 8.00 ppt | Not Detected |
| NEtFOSAA | 6/5/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFHpA | 6/5/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFTrDA | 6/5/2023 | <7.00 ppt | 7.00 ppt | Not Detected |
| PFHxS | 6/5/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFTA | 11/8/2023 | <8.00 ppt | 8.00 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 |
| NMeFOSAA | 11/8/2023 | <6.00 ppt | 6.00 ppt | Not Detected |
| 4:2 FTS | 1/24/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFNA | 1/24/2024 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFOA | 1/24/2024 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFDA | 1/24/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFDoA | 1/24/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHxA | 1/24/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFUnA | 1/24/2024 | <2.00 ppt | 2.00 ppt | Not Detected |
| 11Cl-PF3OUdS | 1/24/2024 | <5.00 ppt | 5.00 ppt | Not Detected |
| 9Cl-PF3ONS | 1/24/2024 | <2.00 ppt | 2.00 ppt | Not Detected |
| ADONA | 1/24/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| HFPO-DA | 1/24/2024 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFBS | 1/24/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| 6:2 FTS | 1/24/2024 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFHpA | 1/24/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
| 8:2 FTS | 1/24/2024 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFMPA | 1/24/2024 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFPeA | 1/24/2024 | <3.00 ppt | 3.00 ppt | Not Detected |
Health-based violations on Prairie Island
0 health-based rows in the tables above map to MCL or treatment-technique exceedances, verify each contaminant code on the federal SDWIS report for 055294502.
Sources: EPA SDWIS
Nationwide peers
188 violations · 6,699 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 Prairie Island
Use this system's EPA-reported record as a starting filter, not a final verdict.
- See how every tracked system in EPA Region 5 — Tribal Water Systems compares on the same EPA violation measures. EPA Region 5 — Tribal Water Systems 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.