San Francisco
CA

Is San Francisco, CA Tap Water Safe to Drink?

San Francisco tap water meets federal Safe Drinking Water Act standards but 1 of 17 ZIP codes show detections above EPA health guidelines, primarily for PFPeA. A certified filter is recommended for households that want an additional layer of protection.

4Water systems
17ZIP codes
5.9%ZIPs above EPA guideline
Metro areaSan Francisco-Oakland-Fremont, CA
Latest data2025-10-29

Where Does San Francisco Get Its Water?

Water in San Francisco, CA is provided by 4 public water systems: PRESIDIO OF SAN FRANCISCO, KOHALA RANCH WATER CO., MONTARA WATER AND SANITARY DISTRICT and SFPUC CITY DISTRIBUTION DIVISION.

How Is San Francisco Tap Water Treated?

Treated water is disinfected using calcium hypochlorite and free chlorine and ozone. Treatment includes conventional treatment (coagulation, flocculation, and filtration) and groundwater disinfection.

What's in San Francisco Tap Water?

The following contaminants were detected most frequently in San Francisco public water systems. 1 of 17 ZIP codes showed detections above EPA health guidelines.

ContaminantPeak detectedEPA guidelineZIPs detectedStatus
PFPeA 0.007 µg/L 0.003 µg/L 1 ZIP Above guideline
lithium 9 µg/L — 0 ZIPs Within guideline
PFTrDA 0.007 µg/L — 0 ZIPs Within guideline
PFHxA 0.0059 µg/L — 1 ZIP Within guideline
6:2 FTS 0.005 µg/L 0.005 µg/L 13 ZIPs Within guideline

Health Risk Profile for San Francisco

Based on EPA monitoring data, 1 of 17 ZIP codes in San Francisco have recorded detections above EPA health guidelines. Sensitive populations such as infants, pregnant individuals, and those with weakened immune systems may benefit from an additional layer of protection such as a certified point-of-use filter.

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.

Waterdrop G3P600 Reverse Osmosis System
Under-sink RO system

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 San Francisco Tap Water

Is San Francisco tap water safe to drink?

San Francisco tap water meets Safe Drinking Water Act requirements but 1 of 17 ZIP codes show contaminant levels above EPA health-based guidelines. A certified point-of-use filter adds an extra layer of protection.

What contaminants are in San Francisco tap water?

The most commonly detected contaminants in San Francisco water systems include: PFPeA, lithium, PFTrDA. See the ZIP-level reports for exact measurements and EPA guideline comparisons.

Where does San Francisco get its drinking water?

San Francisco receives water from 4 public water systems, including PRESIDIO OF SAN FRANCISCO.

Do I need a water filter in San Francisco?

If your ZIP code is among those with detections above EPA health guidelines, choose a filter certified for the specific contaminants shown in your ZIP report. Reverse osmosis is generally the broadest option for PFAS, lithium, and many other dissolved contaminants.

How often is San Francisco tap water tested?

Public water systems in San Francisco 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 2025-10-29.

Tap water reports by ZIP in San Francisco

Water utilities serving San Francisco, 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.

Modeled boundaries are shown with a dashed outline.

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