Is Los Altos Hills, CA Tap Water Safe to Drink?
Los Altos Hills, 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 Los Altos Hills Get Its Water?
Water in Los Altos Hills, CA is provided by 4 public water systems: CALIFORNIA WATER SERVICE - BEAR GULCH, CITY OF PALO ALTO, PURISSIMA HILLS WATER DISTRICT and CWSC LOS ALTOS SUBURBAN.
How Is Los Altos Hills Tap Water Treated?
Treated water is disinfected using free chlorine and calcium hypochlorite. Treatment includes conventional treatment (coagulation, flocculation, and filtration), direct filtration and groundwater disinfection.
What's in Los Altos Hills Tap Water?
The following contaminants were detected most frequently in Los Altos Hills 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 | 0.007 µg/L | 1 ZIP | Within guideline |
| 11Cl-PF3OUdS | 0.005 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 |
Health Risk Profile for Los Altos Hills
Current EPA monitoring data for Los Altos Hills 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 Filters for PFAS Water Profile
PFAS compounds are detected in this water supply. A reverse osmosis (RO) system or an activated-carbon filter specifically certified under NSF/ANSI P473 is required for reliable PFAS reduction. Standard pitcher and faucet filters without P473 certification do not remove PFAS.
8-stage tankless RO system certified to NSF/ANSI 58, reduces 1,000+ contaminants including PFAS, lead, arsenic, fluoride, and nitrates.
NSF-certified dual-layer filtration reduces 70+ contaminants including PFAS, lead, chlorine, microplastics, and bacteria.
See recommendations matched to your exact address: choose your ZIP code below.
Frequently Asked Questions about Los Altos Hills Tap Water
Is Los Altos Hills tap water safe to drink?
Los Altos Hills 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 Los Altos Hills tap water?
The most commonly detected contaminants in Los Altos Hills water systems include: lithium, PFTrDA, 11Cl-PF3OUdS. See the ZIP-level reports for exact measurements and EPA guideline comparisons.
Where does Los Altos Hills get its drinking water?
Los Altos Hills receives water from 4 public water systems, including CALIFORNIA WATER SERVICE - BEAR GULCH.
Do I need a water filter in Los Altos Hills?
Current data does not show guideline exceedances in Los Altos Hills. A certified filter can still reduce trace contaminants and improve taste for households that prefer filtered water.
How often is Los Altos Hills tap water tested?
Public water systems in Los Altos Hills 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 2025-09-16.
Tap water reports by ZIP in Los Altos Hills
- 94022 - Los Altos Hills tap water report Some concern
Water utilities serving Los Altos Hills, 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.
- CWSC LOS ALTOS SUBURBANSome concern
- SANTA CLARA VALLEY WATER DISTRICTNo recent federal sampling
Also covers / overlaps with
- Los Altos, CA
- Palo Alto, CA
- San Jose CCD, CA · Township
- West Santa Clara CCD, CA · Township