Public water system record
Colonial Oak WC Inc
Serves Prunedale, Monterey County, CA · 198 people served
Federal records show 3 health-based violations and 1 monitoring/reporting issue for Colonial Oak WC Inc in the last ten years. The most serious issue in this window was a Nitrate violation that EPA lists as archived, not resolved.
System profile
- Health-based violations, last 10 years
- 3
- Resolved
- 0
- Unresolved
- 0
- Archived by EPA
- 3
- Any acute record
- Yes
- Monitoring issues, last 10 years
- 1
Key facts
- Colonial Oak WC Inc draws water from 4 wells.
- Highest measured level in the last 10 years: Nitrate, 11 mg/L, federal limit 10 mg/L (1.1 times the limit), 2024.
- Most recent formal enforcement: compliance order (no penalty) by California, September 2023.
- Record on file since 1980, with 15 health-based violations before October 19, 2016.
- Lead pipe inventory: 0 lead and 21 unknown out of 66 service lines.
Check whether Colonial Oak WC Inc 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 |
|---|---|---|---|---|
|
Nitrate
Contaminant limit exceeded
Measured 11 mg/L, federal limit 10 mg/L (1.1 times the limit)
|
330 | Jan 1, 2024 |
Archived
Violation period ended. EPA no longer counts it toward current compliance, but no fix was formally recorded.
|
Yes |
|
Nitrate
Contaminant limit exceeded
Measured 11 mg/L, federal limit 10 mg/L (1.1 times the limit)
|
330 | Jul 1, 2023 |
Archived
Violation period ended. EPA no longer counts it toward current compliance, but no fix was formally recorded.
|
Yes |
|
Nitrate
Contaminant limit exceeded
Measured 11 mg/L, federal limit 10 mg/L (1.1 times the limit)
|
330 | Apr 1, 2023 |
Archived
Violation period ended. EPA no longer counts it toward current compliance, but no fix was formally recorded.
|
Yes |
Monitoring and reporting issues
Since October 2016Missed tests or reports, not contaminants found above a limit.
| Issue | Start date | Status |
|---|---|---|
|
LEAD AND COPPER RULE REVISIONS
RPT
|
Jul 2, 2025 | Active |
Full record since 1980
EPA's records for Colonial Oak WC Inc go back to 1980. Before October 19, 2016 they list 15 health-based violations (15 resolved) and 7 monitoring or reporting violations.
| Violations that began in | Health-based | Monitoring and reporting |
|---|---|---|
| 1980s | 0 | 2 |
| 1990s | 0 | 1 |
| 2000s | 6 | 3 |
| 2010 to October 18, 2016 | 9 | 1 |
| 2020s | 3 | 1 |
Most recent health-based violation before October 19, 2016: Total Coliform, began July 2015, Resolved.
Show all 15 health-based violations before October 19, 2016
| Contaminant | Start date | Status |
|---|---|---|
|
Total Coliform
Contaminant limit exceeded
|
Jul 1, 2015 | Resolved |
|
Total Coliform
Contaminant limit exceeded
|
Jun 1, 2015 | Resolved |
|
Total Coliform
Contaminant limit exceeded
|
May 1, 2015 | Resolved |
|
Total Coliform
Contaminant limit exceeded
|
Apr 1, 2015 | Resolved |
|
Total Coliform
Contaminant limit exceeded
|
Jul 1, 2014 | Resolved |
|
Total Coliform
Contaminant limit exceeded
|
Jul 1, 2012 | Resolved |
|
Total Coliform
Contaminant limit exceeded
|
Jun 1, 2012 | Resolved |
|
Total Coliform
Contaminant limit exceeded
|
Dec 1, 2011 | Resolved |
|
Total Coliform
Contaminant limit exceeded
|
Nov 1, 2011 | Resolved |
|
Total Coliform
Contaminant limit exceeded
|
Sep 1, 2007 | Resolved |
|
Total Coliform
Contaminant limit exceeded
|
Nov 1, 2006 | Resolved |
|
Total Coliform
Contaminant limit exceeded
|
Jan 1, 2006 | Resolved |
|
Total Coliform
Contaminant limit exceeded
|
May 1, 2005 | Resolved |
|
Total Coliform
Contaminant limit exceeded
|
Jan 1, 2005 | Resolved |
|
Total Coliform
Contaminant limit exceeded
|
Aug 1, 2003 | Resolved |
Enforcement actions
California regulators took 2 formal enforcement actions against Colonial Oak WC Inc between 2015 and 2023, filed as 3 records in EPA's data. The most recent was a compliance order (no penalty) in September 2023.
| Date | By | Action | Violations covered |
|---|---|---|---|
| Sep 8, 2023 | California | Compliance order (no penalty) | 3 violations (3 health-based): Nitrate |
| Jul 1, 2015 | California | Compliance order (no penalty) | 5 violations (5 health-based): Total Coliform |
What the violations mean
Nitrate
3 incidentsNitrate exceeded the federal limit
High nitrate is especially dangerous for infants under 6 months and can cause blue baby syndrome
Where the water comes from
Colonial Oak WC Inc draws water from 4 wells.
Annual water quality report
Colonial Oak WC Inc 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.
Systems serving 500 or fewer people may meet the rule by telling customers the report is available on request, so you may need to ask Colonial Oak WC Inc for a copy.
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 California.
Certified drinking water labs by state EPA guidance for private wells