Is tap water in Hillsdale (94403) safe to drink?
- San Mateo CCD, CA
- Hillsdale
- Laurel
- Hayward Park
- Redwood Shores
- San Mateo Park
- Silver Penny Mobile Home Park
The short answer for Hillsdale (94403)
San Mateo tap water tested within EPA guidelines across all compounds checked (tested February 2025). See the complete test results, measurements, and what was tested.
The health risk for San Mateo
- All tested compounds were below lab detection limits.
Certified filtration options for common tap-water contaminants.
No compounds above or close to EPA limits in available data.
View all tested compounds
SFWD Intertie · Tested: February 2025
| Compound | Measurement | EPA Limit | Comparison |
|---|---|---|---|
| lithium | <9.000 µg/L | 10 µg/L | Below limit |
| PFHxS | <0.003 µg/L | 0.004 µg/L | Below limit |
| HFPO-DA | <0.005 µg/L | 0.01 µg/L | Below limit |
| PFNA | <0.004 µg/L | 0.01 µg/L | Below limit |
| PFHxA | <0.003 µg/L | 3 µg/L | Below limit |
| PFBA | <0.005 µg/L | 6 µg/L | Below limit |
| 11Cl-PF3OUdS | <0.005 µg/L | 0.005 µg/L | Below limit |
| 4:2 FTS | <0.003 µg/L | 0.003 µg/L | Below limit |
| 6:2 FTS | <0.005 µg/L | 0.005 µg/L | Below limit |
| 8:2 FTS | <0.005 µg/L | 0.005 µg/L | Below limit |
| 9Cl-PF3ONS | <0.002 µg/L | 0.002 µg/L | Below limit |
| ADONA | <0.003 µg/L | 0.003 µg/L | Below limit |
| PFBS | <0.003 µg/L | 0.003 µg/L | Below limit |
| PFDA | <0.003 µg/L | 0.003 µg/L | Below limit |
| PFDoA | <0.003 µg/L | 0.003 µg/L | Below limit |
| PFHpA | <0.003 µg/L | 0.003 µg/L | Below limit |
| PFHpS | <0.003 µg/L | 0.003 µg/L | Below limit |
| PFOA | <0.004 µg/L | 0.004 µg/L | Below limit |
| PFOS | <0.004 µg/L | 0.004 µg/L | Below limit |
| PFPeA | <0.003 µg/L | 0.003 µg/L | Below limit |
| PFTrDA | <0.007 µg/L | 0.007 µg/L | Below limit |
| PFUnA | <0.002 µg/L | 0.002 µg/L | Below limit |
Water utilities serving ZIP 94403
Service area boundaries are approximate and based on state filings or modeled estimates. Contact your utility to confirm exact service at a specific address.
- CALIFORNIA WATER SERVICE - SAN MATEOSome concern
Frequently Asked Questions about ZIP 94403 Tap Water
What's in ZIP 94403 tap water?
ZIP 94403 did not show contaminants above EPA health guidelines in the latest available dataset. The full table on this page lists every compound that was tested.
Who provides tap water in ZIP 94403?
Public records identify CALIFORNIA WATER SERVICE - SAN MATEO as a primary water system associated with ZIP 94403. Service boundaries can vary by address, so confirm exact service with the utility.
When was ZIP 94403 tap water last tested?
The most recent test date used in this report is February 2025. EnviroClarity last refreshed this page on 2026-05-04.
Where can I find the official water quality report for ZIP 94403?
Every U.S. public water system is required to publish an annual Consumer Confidence Report (CCR). Contact CALIFORNIA WATER SERVICE - SAN MATEO or visit their website for the latest official report covering ZIP 94403. The EPA also maintains a national CCR locator.
Do I still need a water filter in ZIP 94403?
Even when EPA-tracked compounds are within limits, some households use a certified filter for taste, odor, or to add a margin against trace contaminants below the reporting limit. Match any filter's certifications (NSF/ANSI 42, 53, 58, or P473) to the specific compounds you care about.
Check another ZIP code
Nearby ZIP reports
- 94002 - Belmont tap water report
- 94402 - San Mateo Park, San Mateo tap water report
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- 94401 - San Mateo Park, San Mateo tap water report
- 94065 - Redwood Shores, Redwood City tap water report
- 94070 - San Carlos tap water report
- 94010 - Hillsborough tap water report
- 94063 - Lindenwood, Redwood City tap water report
Data reflects publicly reported utility records from EPA datasets and local utility disclosures. This information is educational and not medical advice.