Community Water System · PWS IL1630350
Dupo
Operator location Dupo, Illinois - 0% of 8 violations are health-based (lower-third health share (≤ 1%)); groundwater source; 4,684 served per SDWIS.
- 4,684
- People served (this PWS)
- 8
- EPA violations (this PWS)
- 0
- Health-based (this PWS)
- 3 PFAS
- UCMR5 (this PWS)
Dupo standing, low SDWIS violation third
0% of 8 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: middle-third PFAS panel (≤ 4 compounds). Population rank #8,044 of 29,740 among systems serving 500+.
The verdict
Dupo is in the lower third by violation count (8; lower-third violation load (≤ 21 violations)). A low count does not mean the system is unmonitored - monitoring and reporting violations still appear in SDWIS. Population served is large (4,684; 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 detected 3 PFAS compounds (middle-third PFAS panel (≤ 4 compounds)).
- #8,044 of 29,740
- Population · /systems
- #387 of 1,310
- Population · IL
- 8
- 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.
3 PFAS "forever chemicals" detected in testing under EPA's UCMR5 monitoring program.
System Details
- System Type
- Community
- Owner Type
- Local
- Connections
- 2,165
- County
- St. Clair
- School/Daycare
- No
- MCL Violations
- 0
- Monitoring Violations
- 4
- Treatment Tech Violations
- 0
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| Consumer Confidence Rule | Other | 4 | 2024 |
| Coliform (TCR) | MR | 4 | 1998 |
Violation Count vs. the National Corpus
Dupo has 8 recorded EPA violations, 15% of the 29,740 public water systems serving 500+ people nationwide carry fewer, and 83% carry more. 0% of this system's own violations are health-based (0 of 8), and it ranks #8,044 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)
8 Among the lowest violation counts fewer 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. 5 of 58 samples detected PFAS.
| Contaminant | Date | Result | MRL | Status |
|---|---|---|---|---|
| PFHpA | 5/6/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFUnA | 5/6/2025 | <2.00 ppt | 2.00 ppt | Not Detected |
| PFHxA | 5/6/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFDoA | 5/6/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFDA | 5/6/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFOA | 5/6/2025 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFPeA | 5/6/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFOS | 5/6/2025 | 5.60 ppt | 4.00 ppt | Detected |
| PFHxS | 5/6/2025 | 3.10 ppt | 3.00 ppt | Detected |
| PFBS | 5/6/2025 | 3.10 ppt | 3.00 ppt | Detected |
| 9Cl-PF3ONS | 5/6/2025 | <2.00 ppt | 2.00 ppt | Not Detected |
| PFPeS | 5/6/2025 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFMBA | 5/6/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFNA | 5/6/2025 | <4.00 ppt | 4.00 ppt | Not Detected |
| HFPO-DA | 5/6/2025 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFBA | 5/6/2025 | <5.00 ppt | 5.00 ppt | Not Detected |
| 6:2 FTS | 5/6/2025 | <5.00 ppt | 5.00 ppt | Not Detected |
| 4:2 FTS | 5/6/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| 8:2 FTS | 5/6/2025 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFMPA | 5/6/2025 | <4.00 ppt | 4.00 ppt | Not Detected |
| NFDHA | 5/6/2025 | <20.00 ppt | 20.00 ppt | Not Detected |
| PFHpS | 5/6/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFTA | 5/6/2025 | <8.00 ppt | 8.00 ppt | Not Detected |
| PFTrDA | 5/6/2025 | <7.00 ppt | 7.00 ppt | Not Detected |
| NEtFOSAA | 5/6/2025 | <5.00 ppt | 5.00 ppt | Not Detected |
| NMeFOSAA | 5/6/2025 | <6.00 ppt | 6.00 ppt | Not Detected |
| 11Cl-PF3OUdS | 5/6/2025 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFEESA | 5/6/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| ADONA | 5/6/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFOS | 11/3/2025 | 4.50 ppt | 4.00 ppt | Detected |
| PFBA | 11/3/2025 | <5.00 ppt | 5.00 ppt | Not Detected |
| HFPO-DA | 11/3/2025 | <5.00 ppt | 5.00 ppt | Not Detected |
| NEtFOSAA | 11/3/2025 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFTrDA | 11/3/2025 | <7.00 ppt | 7.00 ppt | Not Detected |
| NMeFOSAA | 11/3/2025 | <6.00 ppt | 6.00 ppt | Not Detected |
| 6:2 FTS | 11/3/2025 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFTA | 11/3/2025 | <8.00 ppt | 8.00 ppt | Not Detected |
| PFNA | 11/3/2025 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFHxS | 11/3/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHpA | 11/3/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHpS | 11/3/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFBS | 11/3/2025 | 3.70 ppt | 3.00 ppt | Detected |
| PFOA | 11/3/2025 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFEESA | 11/3/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| NFDHA | 11/3/2025 | <20.00 ppt | 20.00 ppt | Not Detected |
| ADONA | 11/3/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFDA | 11/3/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| 4:2 FTS | 11/3/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| 11Cl-PF3OUdS | 11/3/2025 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFUnA | 11/3/2025 | <2.00 ppt | 2.00 ppt | Not Detected |
Health-based violations on Dupo
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 IL1630350.
Sources: EPA SDWIS · Illinois EPA, Bureau of Water
Nationwide peers
8 violations · 4,684 served: nearest cross-state SDWIS matches.
Cross-state systems with similarly light violation ledgers
Nearest cross-state community systems (500+ served) by total SDWIS violations on record.
- Mohegan Tribal Utility Authority EPA Region 1 — Tribal Water Systems 8violations
- Hannahville Community EPA Region 5 — Tribal Water Systems 8violations
- Quapaw Downstream Casino & Resort EPA Region 6 — Tribal Water Systems 8violations
- San Ildefonso Totavi EPA Region 6 — Tribal Water Systems 8violations
Cross-state systems with similar served population
Nearest cross-state systems by EPA SDWIS population_served (same 500+ sitemap gate).
What to do with Dupo
Use this system's EPA-reported record as a starting filter, not a final verdict.
- See how every tracked system in Illinois compares on the same EPA violation measures. Illinois 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.