Is Foster City, CA Tap Water Safe to Drink?
Foster City, CA tap water currently meets EPA health guidelines across all monitored ZIP codes in this dataset. Contaminants including lithium have been detected at or below guideline thresholds.
Where Does Foster City Get Its Water?
Water in Foster City, CA is provided by 2 public water systems: CALIFORNIA WATER SERVICE - SAN MATEO and ESTERO MUNICIPAL IMPROVEMENT DISTRICT.
How Is Foster City Tap Water Treated?
Treated water is disinfected using calcium hypochlorite and free chlorine. Treatment includes conventional treatment (coagulation, flocculation, and filtration) and direct filtration.
What's in Foster City Tap Water?
The following contaminants were detected most frequently in Foster City public water systems. All detected levels fall at or below EPA health guidelines in this dataset.
| Contaminant | Peak detected | EPA guideline | ZIPs detected | Status |
|---|---|---|---|---|
| lithium | 9 µg/L | — | 0 ZIPs | Within guideline |
| PFTrDA | 0.007 µg/L | — | 0 ZIPs | Within guideline |
| 8:2 FTS | 0.005 µg/L | — | 0 ZIPs | Within guideline |
| 6:2 FTS | 0.005 µg/L | — | 0 ZIPs | Within guideline |
| HFPO-DA | 0.005 µg/L | — | 0 ZIPs | Within guideline |
Health Risk Profile for Foster City
Current EPA monitoring data for Foster City shows contaminant levels within guideline thresholds across all ZIP codes in this dataset. As with all public water systems, sensitive populations may choose to use a certified filter for additional peace of mind.
Best Broad-Spectrum Filters for This Water Profile
This city profile includes PFAS detections, chlorine disinfection, and other dissolved contaminants. Reverse osmosis (RO) systems certified under NSF/ANSI 58 provide broad reduction coverage; for PFAS specifically, confirm NSF/ANSI P473 or equivalent PFAS reduction certification.
8-stage tankless RO system certified to NSF/ANSI 58, reduces 1,000+ contaminants including PFAS, lead, arsenic, fluoride, and nitrates.
See recommendations matched to your exact address: choose your ZIP code below.
Frequently Asked Questions about Foster City Tap Water
Is Foster City tap water safe to drink?
Foster City tap water currently meets EPA health guidelines across all monitored ZIP codes in this dataset. Sensitive populations may still choose to use a certified filter as a precaution.
What contaminants are in Foster City tap water?
The most commonly detected contaminants in Foster City water systems include: lithium, PFTrDA, 8:2 FTS. See the ZIP-level reports for exact measurements and EPA guideline comparisons.
Where does Foster City get its drinking water?
Foster City receives water from 2 public water systems, including CALIFORNIA WATER SERVICE - SAN MATEO.
Do I need a water filter in Foster City?
Current data does not show guideline exceedances in Foster City. A certified filter can still reduce trace contaminants and improve taste for households that prefer filtered water.
How often is Foster City tap water tested?
Public water systems in Foster City are required by the EPA to test for regulated contaminants on schedules ranging from daily (for microbials and disinfectants) to annual or triennial (for many chemical contaminants). Results are published in annual Consumer Confidence Reports (CCRs). The data on this page reflects the most recent available EPA monitoring results, with the latest sample date of 2025-02-03.
Tap water reports by ZIP in Foster City
- 94404 - Foster City tap water report Some concern
Water utilities serving Foster City, CA
Service area boundaries are approximate and based on state filings or modeled estimates. Contact your utility to confirm exact service at a specific address.
Also covers / overlaps with
- San Mateo, CA
- San Mateo CCD, CA · Township