Public water system record
Wonder Lake
Serves Wonder Lake and Bull Valley, McHenry County, IL · 3,870 people served
Federal records show 1 health-based violation and 4 monitoring/reporting issues for Wonder Lake in the last ten years. The most serious issue in this window was a resolved Lead and Copper Rule violation.
System profile
- Health-based violations, last 10 years
- 1
- Resolved
- 1
- Unresolved
- 0
- Any acute record
- No
- Monitoring issues, last 10 years
- 4
Key facts
- Wonder Lake draws water from 6 wells (3 of them for emergency, seasonal or other part-time use).
- Most recent formal enforcement: signed compliance agreement by Illinois, August 2005.
- Record on file since 1977, with 1 health-based violation before October 20, 2016.
- Lead pipe inventory: 0 lead and 0 unknown out of 1,538 service lines.
Check whether Wonder Lake serves your address
Health-based violations
Since October 2016Violation data reflects EPA records through March 2026. For the most current status, visit the EPA ECHO database.
| Contaminant | Rule family | Start date | Status | Acute |
|---|---|---|---|---|
|
Lead and Copper Rule
Treatment technique failure
|
350 | Apr 2, 2023 | Resolved | No |
Monitoring and reporting issues
Since October 2016Missed tests or reports, not contaminants found above a limit.
| Issue | Start date | Status |
|---|---|---|
|
Lead and Copper Rule
Monitoring and reporting
|
Jul 1, 2025 | Active |
|
Lead and Copper Rule
Monitoring and reporting
|
Apr 1, 2025 | Resolved |
|
Public Notice
OTHER
|
Feb 10, 2024 | Resolved |
|
Nitrate
Monitoring and reporting
|
Jan 1, 2022 | Resolved |
Full record since 1977
EPA's records for Wonder Lake go back to 1977. Before October 20, 2016 they list 1 health-based violation (1 archived by EPA without a recorded fix) and 80 monitoring or reporting violations.
| Violations that began in | Health-based | Monitoring and reporting |
|---|---|---|
| 1970s | 0 | 1 |
| 1990s | 0 | 72 |
| 2000s | 1 | 7 |
| 2020s | 1 | 4 |
Most recent health-based violation before October 20, 2016: Total Coliform, began January 2001, Archived.
Show the health-based violation before October 20, 2016
| Contaminant | Start date | Status |
|---|---|---|
|
Total Coliform
Contaminant limit exceeded
|
Jan 1, 2001 | Archived |
Enforcement actions
Illinois regulators took 1 formal enforcement action against Wonder Lake in 2005. The most recent was a signed compliance agreement in August 2005.
| Date | By | Action | Violations covered |
|---|---|---|---|
| Aug 5, 2005 | Illinois | Signed compliance agreement | 3 violations: Lead and Copper Rule, Public Notice |
What the violations mean
Lead and Copper Rule
1 incidentThe system did not complete a treatment step or action that the Lead and Copper Rule requires (a treatment technique violation).
The utility had to notify customers about this violation.
Where the water comes from
Wonder Lake draws water from 6 wells (3 of them for emergency, seasonal or other part-time use). 1 smaller public system such as schools, businesses or campgrounds buys water from Wonder Lake.
Annual water quality report
Wonder Lake must give its customers an annual water quality report (Consumer Confidence Report) by July 1, with the levels its tests found in the previous year.
Where the state allows it, systems serving fewer than 10,000 people may publish the report in a local newspaper or news site instead of mailing it, and must provide a copy on request.
Find a posted report with EPA's Consumer Confidence Report search
Testing your own water
To test the water at your tap, or a private well this record does not cover, use a laboratory certified for drinking water by Illinois.
Certified drinking water labs by state EPA guidance for private wells