Public water system record
Yosemite West Water System
Serves Yosemite West, Mariposa County, CA · 420 people served
Federal records show no health-based violations and 1 monitoring/reporting issue for Yosemite West Water System in the last ten years. At least one of these issues remains unresolved.
System profile
- Health-based violations, last 10 years
- 0
- Resolved
- 0
- Unresolved
- 0
- Any acute record
- No
- Monitoring issues, last 10 years
- 1
Key facts
- Yosemite West Water System draws water from 1 well.
- Most recent formal enforcement: compliance order (no penalty) by California, February 2013.
- Record on file since 1993, with 7 health-based violations before October 20, 2016.
- Lead pipe inventory: 0 lead and 0 unknown out of 298 service lines.
Check whether Yosemite West Water System 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.
None since October 2016.
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
|
Oct 1, 2025 | Active |
Full record since 1993
EPA's records for Yosemite West Water System go back to 1993. Before October 20, 2016 they list 7 health-based violations (7 resolved) and 6 monitoring or reporting violations.
| Violations that began in | Health-based | Monitoring and reporting |
|---|---|---|
| 1990s | 2 | 1 |
| 2000s | 3 | 4 |
| 2010 to October 19, 2016 | 2 | 1 |
| 2020s | 0 | 1 |
Most recent health-based violation before October 20, 2016: Total Coliform, began July 2011, Resolved.
Show all 7 health-based violations before October 20, 2016
| Contaminant | Start date | Status |
|---|---|---|
|
Total Coliform
Contaminant limit exceeded
|
Jul 1, 2011 | Resolved |
|
Total Coliform
Contaminant limit exceeded
|
Oct 1, 2010 | Resolved |
|
Total Coliform
Contaminant limit exceeded
|
Sep 1, 2009 | Resolved |
|
Total Coliform
Contaminant limit exceeded
|
Sep 1, 2008 | Resolved |
|
Total Coliform
Contaminant limit exceeded
|
Jun 1, 2002 | Resolved |
|
Total Coliform
Contaminant limit exceeded
|
Dec 1, 1996 | Resolved |
|
Total Coliform
Contaminant limit exceeded
|
May 1, 1994 | Resolved |
Enforcement actions
California regulators took 7 formal enforcement actions against Yosemite West Water System between 2002 and 2013. The most recent was a compliance order (no penalty) in February 2013.
| Date | By | Action | Violations covered |
|---|---|---|---|
| Feb 25, 2013 | California | Compliance order (no penalty) | 1 violation: Nitrate |
| Aug 1, 2011 | California | Compliance order (no penalty) | 1 violation (1 health-based): Total Coliform |
| Oct 27, 2010 | California | Compliance order (no penalty) | 1 violation (1 health-based): Total Coliform |
| Oct 21, 2009 | California | Compliance order (no penalty) | 1 violation (1 health-based): Total Coliform |
| Sep 22, 2008 | California | Compliance order (no penalty) | 1 violation (1 health-based): Total Coliform |
| Sep 7, 2005 | California | Compliance order (no penalty) | 1 violation: Lead and Copper Rule |
| Jul 30, 2002 | California | Compliance order (no penalty) | 1 violation (1 health-based): Total Coliform |
Where the water comes from
Yosemite West Water System draws water from 1 well.
Annual water quality report
Yosemite West Water System 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 Yosemite West Water System 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