Community Water System · PWS IL1110400
Lake in the Hills
Operator location Lake in the Hills, Illinois - 35% of 52 violations are health-based (upper-third health share (> 23%)); groundwater source; 28,661 served per SDWIS.
- 28,661
- People served (this PWS)
- 52
- EPA violations (this PWS)
- 18
- Health-based (this PWS)
- No PFAS
- UCMR5 (this PWS)
Lake in the Hills standing, mid SDWIS violation third
35% of 52 recorded violations are health-based - upper-third health share (> 23%). Corpus terciles use 29,740 systems serving 500+ (the sitemap cohort). Health-based share 35% is upper-third health share (> 23%). UCMR5: UCMR5 tested, none detected. Population rank #1,956 of 29,740 among systems serving 500+.
The verdict
Lake in the Hills lands in the middle third by violation volume (52), large enough for peer comparisons without matching the fleet's heaviest ledgers. Population served is large (28,661; larger served population (> 3,309)), so household exposure scale sits behind the violation mix. Health-based share is 35% - most of this ledger is MCL or treatment-technique exceedance. UCMR5 tested this system and reported no PFAS above the minimum reporting level.
- #1,956 of 29,740
- Population · /systems
- #78 of 1,310
- Population · IL
- 52
- Total EPA violations on record
- 35%
- 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
- Local
- Connections
- 9,590
- County
- McHenry
- School/Daycare
- No
- MCL Violations
- 18
- Monitoring Violations
- 18
- Treatment Tech Violations
- 0
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| Coliform (TCR) | MCL | 11 | 2012 |
| Combined Radium (-226 and -228) | MCL | 7 | 1984 |
| Coliform (TCR) | MR | 7 | 1997 |
| Nitrate | MR | 5 | 2006 |
| Barium | MR | 3 | 1999 |
| Consumer Confidence Rule | Other | 2 | 2012 |
| Public Notice | Other | 2 | 2005 |
| Gross Alpha, Excl. Radon and U | MR | 1 | 1977 |
| TTHM | MR | 1 | 2025 |
| Total Haloacetic Acids (HAA5) | MR | 1 | 2025 |
Violation Count vs. the National Corpus
Lake in the Hills has 52 recorded EPA violations, 57% of the 29,740 public water systems serving 500+ people nationwide carry fewer, and 42% carry more. 35% of this system's own violations are health-based (18 of 52), and it ranks #1,956 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)
52 Around the middle fewer violations than 42% 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 464 samples detected PFAS.
| Contaminant | Date | Result | MRL | Status |
|---|---|---|---|---|
| PFBS | 4/9/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFOS | 4/9/2025 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFOA | 4/9/2025 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFDA | 4/9/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFDoA | 4/9/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFMPA | 4/9/2025 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFPeA | 4/9/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFTrDA | 4/9/2025 | <7.00 ppt | 7.00 ppt | Not Detected |
| PFHpS | 4/9/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFMBA | 4/9/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFEESA | 4/9/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| NFDHA | 4/9/2025 | <20.00 ppt | 20.00 ppt | Not Detected |
| PFPeS | 4/9/2025 | <4.00 ppt | 4.00 ppt | Not Detected |
| NMeFOSAA | 4/9/2025 | <6.00 ppt | 6.00 ppt | Not Detected |
| PFTA | 4/9/2025 | <8.00 ppt | 8.00 ppt | Not Detected |
| 9Cl-PF3ONS | 4/9/2025 | <2.00 ppt | 2.00 ppt | Not Detected |
| PFHpA | 4/9/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHxS | 4/9/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| NEtFOSAA | 4/9/2025 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFHxA | 4/9/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| 11Cl-PF3OUdS | 4/9/2025 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFNA | 4/9/2025 | <4.00 ppt | 4.00 ppt | Not Detected |
| ADONA | 4/9/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| HFPO-DA | 4/9/2025 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFBA | 4/9/2025 | <5.00 ppt | 5.00 ppt | Not Detected |
| 6:2 FTS | 4/9/2025 | <5.00 ppt | 5.00 ppt | Not Detected |
| 4:2 FTS | 4/9/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| 8:2 FTS | 4/9/2025 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFUnA | 4/9/2025 | <2.00 ppt | 2.00 ppt | Not Detected |
| PFTrDA | 4/9/2025 | <7.00 ppt | 7.00 ppt | Not Detected |
| PFTA | 4/9/2025 | <8.00 ppt | 8.00 ppt | Not Detected |
| ADONA | 4/9/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHpS | 4/9/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFPeS | 4/9/2025 | <4.00 ppt | 4.00 ppt | Not Detected |
| NFDHA | 4/9/2025 | <20.00 ppt | 20.00 ppt | Not Detected |
| PFEESA | 4/9/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFMBA | 4/9/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFPeA | 4/9/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| NEtFOSAA | 4/9/2025 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFMPA | 4/9/2025 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFHpA | 4/9/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| 8:2 FTS | 4/9/2025 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFBS | 4/9/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| HFPO-DA | 4/9/2025 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFOS | 4/9/2025 | <4.00 ppt | 4.00 ppt | Not Detected |
| NMeFOSAA | 4/9/2025 | <6.00 ppt | 6.00 ppt | Not Detected |
| 11Cl-PF3OUdS | 4/9/2025 | <5.00 ppt | 5.00 ppt | Not Detected |
| 6:2 FTS | 4/9/2025 | <5.00 ppt | 5.00 ppt | Not Detected |
| 4:2 FTS | 4/9/2025 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFBA | 4/9/2025 | <5.00 ppt | 5.00 ppt | Not Detected |
Health-based violations on Lake in the Hills
18 health-based rows in the tables above map to MCL or treatment-technique exceedances, verify each contaminant code on the federal SDWIS report for IL1110400.
Sources: EPA SDWIS · Illinois EPA, Bureau of Water
Nationwide peers
52 violations · 28,661 served: nearest cross-state SDWIS matches.
Cross-state systems near this violation count
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 Lake in the Hills
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.