Mariposa Water Quality
California
According to EPA SDWIS, Mariposa, California is served by 5 community water systems covering about 3,695 people. The same extract lists 40 health-based violation records, most recently coded 5200 in 2024. Counts are historical EPA registry rows, not a current compliance or drinkability score.
Drinking water in Mariposa, California is delivered through 5 EPA-regulated community water systems serving an estimated 3,695 people. Each system is tracked in the EPA Safe Drinking Water Information System (SDWIS) under the Safe Drinking Water Act, which requires testing for regulated contaminants, consumer notification of violations, and publication of an annual Consumer Confidence Report.
PlainEnviro's health-based SDWIS extract shows 40 violation records across the 5 active community systems shown here. Monitoring and reporting records are not present in the extract. The records carry 4 distinct EPA contaminant codes: LEAD AND COPPER RULE REVISIONS, Coliform (TCR), Total Haloacetic Acids (HAA5), TTHM.
A past EPA health-based registry row does not describe water delivered today or current compliance status; utilities notify customers and remediate under state primacy oversight when required. For current water-quality status and treatment practices, review your local utility's most recent Consumer Confidence Report or contact the California drinking water program. All records above reflect federal EPA SDWIS data and are not independently verified against state databases.
Community Water Systems
| System Name | Pop. Served | Violations | Status |
|---|---|---|---|
| MARIPOSA PUBLIC UTILITY DIST | 2,000 | 38 | Health |
| PONDEROSA BASIN MUTUAL WTR CO | 798 | 0 | Clean |
| YOSEMITE WEST WATER SYSTEM | 420 | 0 | Clean |
| MARIPOSA PINES MUTUAL | 284 | 2 | Health |
| MPWD-COULTERVILLE CSA 1 | 193 | 0 | Clean |
Does this city have health-based water violations?
These health-based records can represent Maximum Contaminant Level (MCL), Treatment Technique (TT), or Maximum Residual Disinfectant Level (MRDL) categories. A historical record does not establish that water is currently unsafe.
| Water system | Contaminant | Begin Date |
|---|---|---|
| MARIPOSA PINES MUTUAL | LEAD AND COPPER RULE REVISIONS | 2024-10-17 |
| MARIPOSA PINES MUTUAL | Coliform (TCR) | 2015-10-01 |
| MARIPOSA PUBLIC UTILITY DIST | Total Haloacetic Acids (HAA5) | 2012-10-01 |
| MARIPOSA PUBLIC UTILITY DIST | Total Haloacetic Acids (HAA5) | 2012-10-01 |
| MARIPOSA PUBLIC UTILITY DIST | Total Haloacetic Acids (HAA5) | 2012-07-01 |
| MARIPOSA PUBLIC UTILITY DIST | TTHM | 2012-07-01 |
| MARIPOSA PUBLIC UTILITY DIST | TTHM | 2012-04-01 |
| MARIPOSA PUBLIC UTILITY DIST | Total Haloacetic Acids (HAA5) | 2012-04-01 |
| MARIPOSA PUBLIC UTILITY DIST | Total Haloacetic Acids (HAA5) | 2012-01-01 |
| MARIPOSA PUBLIC UTILITY DIST | TTHM | 2012-01-01 |
| MARIPOSA PUBLIC UTILITY DIST | TTHM | 2011-04-01 |
| MARIPOSA PUBLIC UTILITY DIST | Total Haloacetic Acids (HAA5) | 2011-04-01 |
| MARIPOSA PUBLIC UTILITY DIST | TTHM | 2011-01-01 |
| MARIPOSA PUBLIC UTILITY DIST | Total Haloacetic Acids (HAA5) | 2011-01-01 |
| MARIPOSA PUBLIC UTILITY DIST | Total Haloacetic Acids (HAA5) | 2009-07-01 |
| MARIPOSA PUBLIC UTILITY DIST | Total Haloacetic Acids (HAA5) | 2009-04-01 |
| MARIPOSA PUBLIC UTILITY DIST | Total Haloacetic Acids (HAA5) | 2009-01-01 |
| MARIPOSA PUBLIC UTILITY DIST | Total Haloacetic Acids (HAA5) | 2008-07-01 |
| MARIPOSA PUBLIC UTILITY DIST | Total Haloacetic Acids (HAA5) | 2008-04-01 |
| MARIPOSA PUBLIC UTILITY DIST | Total Haloacetic Acids (HAA5) | 2008-01-01 |
| MARIPOSA PUBLIC UTILITY DIST | Total Haloacetic Acids (HAA5) | 2007-10-01 |
| MARIPOSA PUBLIC UTILITY DIST | Total Haloacetic Acids (HAA5) | 2007-07-01 |
| MARIPOSA PUBLIC UTILITY DIST | Total Haloacetic Acids (HAA5) | 2007-04-01 |
| MARIPOSA PUBLIC UTILITY DIST | Total Haloacetic Acids (HAA5) | 2007-01-01 |
| MARIPOSA PUBLIC UTILITY DIST | Total Haloacetic Acids (HAA5) | 2006-10-01 |
| MARIPOSA PUBLIC UTILITY DIST | Total Haloacetic Acids (HAA5) | 2006-07-01 |
| MARIPOSA PUBLIC UTILITY DIST | TTHM | 2006-04-01 |
| MARIPOSA PUBLIC UTILITY DIST | Total Haloacetic Acids (HAA5) | 2006-04-01 |
| MARIPOSA PUBLIC UTILITY DIST | Total Haloacetic Acids (HAA5) | 2005-04-01 |
| MARIPOSA PUBLIC UTILITY DIST | TTHM | 2005-04-01 |
| MARIPOSA PUBLIC UTILITY DIST | Total Haloacetic Acids (HAA5) | 2005-01-01 |
| MARIPOSA PUBLIC UTILITY DIST | TTHM | 2005-01-01 |
| MARIPOSA PUBLIC UTILITY DIST | Total Haloacetic Acids (HAA5) | 2004-10-01 |
| MARIPOSA PUBLIC UTILITY DIST | TTHM | 2004-10-01 |
| MARIPOSA PUBLIC UTILITY DIST | Total Haloacetic Acids (HAA5) | 2004-07-01 |
| MARIPOSA PUBLIC UTILITY DIST | TTHM | 2004-07-01 |
| MARIPOSA PUBLIC UTILITY DIST | TTHM | 2004-04-01 |
| MARIPOSA PUBLIC UTILITY DIST | Total Haloacetic Acids (HAA5) | 2004-04-01 |
| MARIPOSA PUBLIC UTILITY DIST | TTHM | 2004-01-01 |
| MARIPOSA PUBLIC UTILITY DIST | Total Haloacetic Acids (HAA5) | 2004-01-01 |
Frequently Asked Questions
What does EPA SDWIS list for drinking water in Mariposa, California? ▼
How many water violations does Mariposa have in this EPA extract? ▼
What contaminants were found in Mariposa water? ▼
How many water systems serve Mariposa? ▼
Where does Mariposa get its drinking water? ▼
How does Mariposa compare in California?
Of the 912 California places with at least one community water system on file, Mariposa ranks #143 by number of systems (5).
Either side of it: Livermore (5), Lompoc (5), Marysville (5), Middletown (5)
About This Data
Figures here are the current EPA SDWIS extract joined to the 5 community water systems whose service area lists Mariposa, ranked against the 912 California places with at least one system on file. Data current as of 2026-08-25.
Water system data comes from the EPA's Safe Drinking Water Information System (SDWIS). PlainEnviro's violation fetch is restricted upstream to records EPA flags as health-based and then joined to active community water systems. Monitoring and reporting violations are not included.
A health-based violation row in this extract is a historical EPA registry entry. It does not describe water delivered today or current compliance status. Many records are later resolved, and public water systems notify customers when required. For current conditions, contact your local water utility or the state drinking water program.
TRI facility data comes from the EPA Toxic Release Inventory. Facilities shown are those that self-report to the TRI program. PlainEnviro presents this data without advocacy framing.
Read our methodology - how this data is sourced, computed, and verified.