San Mateo Water Quality
California
According to EPA SDWIS, San Mateo, California is served by 4 community water systems covering about 271 people. The same extract lists 24 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 San Mateo, California is delivered through 4 EPA-regulated community water systems serving an estimated 271 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 24 violation records across the 4 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, Nitrate, Revised Total Coliform Rule, Groundwater Rule.
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 |
|---|---|---|---|
| LAZY B MOBILEHOME PARK | 125 | 6 | Health |
| MOUNTAIN VIEW MOBILE HOME PARK | 75 | 9 | Health |
| SHIRK MOBILE HOME PARK | 39 | 8 | Health |
| BLUE LAKES MOBILE HOME PARK | 32 | 1 | Health |
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 |
|---|---|---|
| SHIRK MOBILE HOME PARK | LEAD AND COPPER RULE REVISIONS | 2024-10-17 |
| BLUE LAKES MOBILE HOME PARK | LEAD AND COPPER RULE REVISIONS | 2024-10-17 |
| LAZY B MOBILEHOME PARK | Nitrate | 2024-01-01 |
| LAZY B MOBILEHOME PARK | Nitrate | 2024-01-01 |
| LAZY B MOBILEHOME PARK | Nitrate | 2024-01-01 |
| LAZY B MOBILEHOME PARK | Nitrate | 2023-10-01 |
| LAZY B MOBILEHOME PARK | Nitrate | 2023-10-01 |
| LAZY B MOBILEHOME PARK | Nitrate | 2023-10-01 |
| SHIRK MOBILE HOME PARK | Revised Total Coliform Rule | 2017-12-22 |
| MOUNTAIN VIEW MOBILE HOME PARK | Revised Total Coliform Rule | 2017-08-14 |
| MOUNTAIN VIEW MOBILE HOME PARK | Groundwater Rule | 2015-03-05 |
| MOUNTAIN VIEW MOBILE HOME PARK | Groundwater Rule | 2015-03-05 |
| MOUNTAIN VIEW MOBILE HOME PARK | Groundwater Rule | 2015-03-05 |
| MOUNTAIN VIEW MOBILE HOME PARK | Groundwater Rule | 2015-03-05 |
| MOUNTAIN VIEW MOBILE HOME PARK | Groundwater Rule | 2014-12-08 |
| MOUNTAIN VIEW MOBILE HOME PARK | Groundwater Rule | 2014-12-08 |
| MOUNTAIN VIEW MOBILE HOME PARK | Groundwater Rule | 2014-12-08 |
| MOUNTAIN VIEW MOBILE HOME PARK | Groundwater Rule | 2014-12-08 |
| SHIRK MOBILE HOME PARK | Groundwater Rule | 2014-03-02 |
| SHIRK MOBILE HOME PARK | Groundwater Rule | 2014-03-02 |
| SHIRK MOBILE HOME PARK | Groundwater Rule | 2014-03-02 |
| SHIRK MOBILE HOME PARK | Groundwater Rule | 2013-12-05 |
| SHIRK MOBILE HOME PARK | Groundwater Rule | 2013-12-05 |
| SHIRK MOBILE HOME PARK | Groundwater Rule | 2013-12-05 |
Frequently Asked Questions
What does EPA SDWIS list for drinking water in San Mateo, California? ▼
How many water violations does San Mateo have in this EPA extract? ▼
What contaminants were found in San Mateo water? ▼
How many water systems serve San Mateo? ▼
Where does San Mateo get its drinking water? ▼
How does San Mateo compare in California?
Of the 912 California places with at least one community water system on file, San Mateo ranks #204 by number of systems (4).
Either side of it: San Juan Bautista (4), San Juan Capistrano (4), Shafter (4), Shingletown (4)
About This Data
Figures here are the current EPA SDWIS extract joined to the 4 community water systems whose service area lists San Mateo, 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.