Community Water System · PWS IL1110600
McHenry
Operator location McHenry, Illinois - UCMR5 detected 1 PFAS compound (lower-third PFAS panel (≤ 2 compounds)) on this PWS; SDWIS lists 101 violations and 22,335 people served.
- 22,335
- People served (this PWS)
- 101
- EPA violations (this PWS)
- 4
- Health-based (this PWS)
- 1 PFAS
- UCMR5 (this PWS)
McHenry standing, high SDWIS violation third
UCMR5 detected 1 PFAS compound - lower-third PFAS panel (≤ 2 compounds). Corpus terciles use 29,740 systems serving 500+ (the sitemap cohort). Health-based share 4% is middle-third health share (≤ 23%). UCMR5: lower-third PFAS panel (≤ 2 compounds). Population rank #2,476 of 29,740 among systems serving 500+.
The verdict
McHenry sits in the upper third of the sitemap cohort by violation count (101), so the tables below sample a dense compliance trail rather than a near-clean ledger. Population served is large (22,335; larger served population (> 3,309)), so household exposure scale sits behind the violation mix. Health-based share is 4% (middle-third health share (≤ 23%)). UCMR5 detected 1 PFAS compound (lower-third PFAS panel (≤ 2 compounds)).
- #2,476 of 29,740
- Population · /systems
- #109 of 1,310
- Population · IL
- 101
- Total EPA violations on record
- 4%
- Health-based (MCL / treatment failure)
Population ordinals match the sitemap cohort (systems serving 500+, population_served DESC). See methodology · corpus placement.
1 PFAS "forever chemicals" detected in testing under EPA's UCMR5 monitoring program.
System Details
- System Type
- Community
- Owner Type
- Local
- Connections
- 8,484
- County
- McHenry
- School/Daycare
- No
- MCL Violations
- 2
- Monitoring Violations
- 93
- Treatment Tech Violations
- 2
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| Lead and Copper Rule | MR | 8 | 2025 |
| Vinyl chloride | MR | 4 | 2023 |
| o-Dichlorobenzene | MR | 4 | 2023 |
| 1,2-Dichloropropane | MR | 4 | 2023 |
| 1,1,2-Trichloroethane | MR | 4 | 2023 |
| Tetrachloroethylene | MR | 4 | 2023 |
| CHLOROBENZENE | MR | 4 | 2023 |
| Toluene | MR | 4 | 2023 |
| DICHLOROMETHANE | MR | 4 | 2023 |
| Xylenes, Total | MR | 4 | 2023 |
| Trichloroethylene | MR | 4 | 2023 |
| 1,1-Dichloroethylene | MR | 4 | 2023 |
| cis-1,2-Dichloroethylene | MR | 4 | 2023 |
| Benzene | MR | 4 | 2023 |
| Carbon tetrachloride | MR | 4 | 2023 |
| 1,2,4-Trichlorobenzene | MR | 4 | 2023 |
| p-Dichlorobenzene | MR | 4 | 2023 |
| Styrene | MR | 4 | 2023 |
| 1,2-Dichloroethane | MR | 4 | 2023 |
| Ethylbenzene | MR | 4 | 2023 |
| trans-1,2-Dichloroethylene | MR | 4 | 2023 |
| 1,1,1-Trichloroethane | MR | 4 | 2023 |
| Coliform (TCR) | MCL | 2 | 1996 |
| Lead and Copper Rule | TT | 2 | 1992 |
| Gross Alpha, Excl. Radon and U | MR | 1 | 1977 |
Violation Count vs. the National Corpus
McHenry has 101 recorded EPA violations, 73% of the 29,740 public water systems serving 500+ people nationwide carry fewer, and 26% carry more. 4% of this system's own violations are health-based (4 of 101), and it ranks #2,476 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)
101 Around the middle fewer violations than 26% 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. 1 of 232 samples detected PFAS.
| Contaminant | Date | Result | MRL | Status |
|---|---|---|---|---|
| PFTA | 5/23/2023 | <8.00 ppt | 8.00 ppt | Not Detected |
| NEtFOSAA | 5/23/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| NMeFOSAA | 5/23/2023 | <6.00 ppt | 6.00 ppt | Not Detected |
| PFTrDA | 5/23/2023 | <7.00 ppt | 7.00 ppt | Not Detected |
| 4:2 FTS | 5/23/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| 6:2 FTS | 5/23/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| NFDHA | 5/23/2023 | <20.00 ppt | 20.00 ppt | Not Detected |
| 8:2 FTS | 5/23/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFPeA | 5/23/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFEESA | 5/23/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFPeS | 5/23/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFHpS | 5/23/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFTA | 5/23/2023 | <8.00 ppt | 8.00 ppt | Not Detected |
| PFTrDA | 5/23/2023 | <7.00 ppt | 7.00 ppt | Not Detected |
| NMeFOSAA | 5/23/2023 | <6.00 ppt | 6.00 ppt | Not Detected |
| PFBA | 5/23/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFMBA | 5/23/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| NEtFOSAA | 5/23/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| HFPO-DA | 5/23/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| ADONA | 5/23/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| 9Cl-PF3ONS | 5/23/2023 | <2.00 ppt | 2.00 ppt | Not Detected |
| 11Cl-PF3OUdS | 5/23/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFUnA | 5/23/2023 | <2.00 ppt | 2.00 ppt | Not Detected |
| PFHxA | 5/23/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFDoA | 5/23/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFDA | 5/23/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFOA | 5/23/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFOS | 5/23/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFNA | 5/23/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFHxS | 5/23/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFBS | 5/23/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHpA | 5/23/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFMPA | 5/23/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFPeA | 5/23/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFMBA | 5/23/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFEESA | 5/23/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| NFDHA | 5/23/2023 | <20.00 ppt | 20.00 ppt | Not Detected |
| PFPeS | 5/23/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| 8:2 FTS | 5/23/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| HFPO-DA | 5/23/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| 4:2 FTS | 5/23/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFTA | 5/23/2023 | <8.00 ppt | 8.00 ppt | Not Detected |
| NMeFOSAA | 5/23/2023 | <6.00 ppt | 6.00 ppt | Not Detected |
| NEtFOSAA | 5/23/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFHpS | 5/23/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFDoA | 5/23/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHpA | 5/23/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFBS | 5/23/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFNA | 5/23/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFTrDA | 5/23/2023 | <7.00 ppt | 7.00 ppt | Not Detected |
UCMR5 PFAS record for McHenry
Open EPA SDWIS federal reports for PWS IL1110600 to cross-check UCMR5 detections and violation codes; state primacy agencies enforce the Safe Drinking Water Act locally.
Sources: EPA SDWIS · Illinois EPA, Bureau of Water
Nationwide peers
101 violations · 22,335 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 McHenry
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.