Public water system record
Ontario Waterworks
Serves Ontario, Vernon County, WI · 554 people served
Federal records show 1 health-based violation and 4 monitoring/reporting issues for Ontario Waterworks in the last ten years. The most serious issue in this window was a resolved LEAD AND COPPER RULE REVISIONS 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
- Ontario Waterworks draws water from 2 wells.
- Record on file since 1993, with 11 health-based violations before October 19, 2016.
- Lead pipe inventory: 0 lead and 238 unknown out of 309 service lines.
Check whether Ontario Waterworks 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 REVISIONS
Treatment technique failure
|
350 | Oct 17, 2024 | Resolved | No |
Monitoring and reporting issues
Since October 2016Missed tests or reports, not contaminants found above a limit.
| Issue | Start date | Status |
|---|---|---|
|
Revised Total Coliform Rule
Monitoring violation
|
Jul 1, 2025 | Resolved |
|
Total Trihalomethanes (TTHMs)
Monitoring and reporting
|
Jan 1, 2025 |
Archived
Violation period ended. EPA no longer counts it toward current compliance, but no fix was formally recorded.
|
|
Haloacetic Acids (HAA5)
Monitoring and reporting
|
Jan 1, 2025 |
Archived
Violation period ended. EPA no longer counts it toward current compliance, but no fix was formally recorded.
|
|
Public Notice
OTHER
|
Oct 17, 2024 | Active |
Full record since 1993
EPA's records for Ontario Waterworks go back to 1993. Before October 19, 2016 they list 11 health-based violations (11 resolved) and 3 monitoring or reporting violations.
| Violations that began in | Health-based | Monitoring and reporting |
|---|---|---|
| 1990s | 9 | 1 |
| 2000s | 2 | 2 |
| 2020s | 1 | 4 |
Most recent health-based violation before October 19, 2016: Total Coliform, began June 2006, Resolved.
Show all 11 health-based violations before October 19, 2016
| Contaminant | Start date | Status |
|---|---|---|
|
Total Coliform
Contaminant limit exceeded
|
Jun 1, 2006 | Resolved |
|
Total Coliform
Contaminant limit exceeded
|
Oct 1, 2001 | Resolved |
|
Total Coliform
Contaminant limit exceeded
|
May 1, 1998 | Resolved |
|
Total Coliform
Contaminant limit exceeded
|
Oct 1, 1997 | Resolved |
|
Total Coliform
Contaminant limit exceeded
|
May 1, 1996 | Resolved |
|
Total Coliform
Contaminant limit exceeded
|
May 1, 1995 | Resolved |
|
Total Coliform
Contaminant limit exceeded
|
Aug 1, 1994 | Resolved |
|
Total Coliform
Contaminant limit exceeded
|
Aug 1, 1994 | Resolved |
|
Total Coliform
Contaminant limit exceeded
|
Oct 1, 1993 | Resolved |
|
Total Coliform
Contaminant limit exceeded
|
Aug 1, 1993 | Resolved |
|
Total Coliform
Contaminant limit exceeded
|
May 1, 1993 | Resolved |
What the violations mean
LEAD AND COPPER RULE REVISIONS
1 incidentThe system did not complete a treatment step or action that the LEAD AND COPPER RULE REVISIONS requires (a treatment technique violation).
The utility had to notify customers about this violation.
Where the water comes from
Ontario Waterworks draws water from 2 wells.
Annual water quality report
Ontario Waterworks 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 Wisconsin.
Certified drinking water labs by state EPA guidance for private wells