Water Quality & Forever Chemicals
Late-night search for "is San Francisco tap water safe"? Here's the plain answer to what this page is: a gathering of what public federal water records show for San Francisco, organized so you don't have to wade through the datasets yourself. It's not a verdict on your particular glass. What actually varies block to block is the system serving your address and the sources feeding it, and that's the piece worth chasing down for your specific home.
7
PFAS detections in nearby water systems
EPA UCMR 5 (2021–2024) results matching the city name
0
Industrial PFAS facilities in city
EPA TRI 2024 reporting
11
DoD PFAS installations statewide
In California
Much of San Francisco's supply is widely understood to come from the Hetch Hetchy system, with water originating largely as Sierra Nevada snowmelt stored upcountry and delivered across the region. The city tends to rely heavily on that high-elevation surface source, supplemented at times by local and Bay Area supplies. As with any system, the exact mix can shift with drought and operations, so treat this as the well-established broad picture.
In San Francisco it's easy to assume everyone drinks from the same famous source, but who serves your address is still worth confirming, especially near the city's edges and neighboring communities on different public water systems. The utility above reflects federal records; a building across a boundary line may not match. When evaluating an address, it's worth reviewing the system's annual Consumer Confidence Report and calling the utility listed for you. Free, quick, and far more specific than any citywide summary can be.
If your San Francisco soap lathers easily and your glassware stays clear, you may be quietly benefiting from softer water, a low-stakes quality-of-life thing rather than a safety matter. Sierra snowmelt-fed supplies across much of the region tend toward the softer end, though your tap depends on your system. We won't put a number on it without data; instead, a cheap test strip or your utility's annual report, which often lists hardness, will tell you what's actually coming out of your pipes.
EPA required public water systems serving 3,300+ people to test 29 PFAS compounds between 2021 and 2024.
City-level numbers describe the broad pattern around San Francisco; two homes a mile apart can sit on different water systems with very different profiles. The address report fills that gap — it identifies the public water system serving a specific property, lists any PFAS detections on that exact system, and maps the nearby industrial and Superfund sources.
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EPA data tells you what your utility reported on the days they tested. A Tap Score kit tells you what's coming out of your faucet, right now. Mail-in lab, certified results in about a week. The same labs cities use.
Order a Tap Score kit →Guide
How to Check Drinking Water Quality Before Buying a Home
The 5-minute version of what an environmental consultant would look at.
Guide
PFAS “Forever Chemicals” — A Homebuyer's Guide
What PFAS are, why they matter, and what to do before closing.
How-to
How to Check for PFAS Near Your Address
A walkthrough of the federal datasets we pull from.
Checklist
Environmental Risks to Check Before Buying a House
A practical pre-offer checklist for buyers and agents.
This page reflects what federal public records like UCMR 5 show for San Francisco, not a safety verdict. Detection in those records isn't the same as an exceedance, and since the program covers larger systems, a quiet result means no matching records here rather than a certified clean rating. The only address-level answer comes from checking the specific system that serves you.
Look first at the system or systems listed on this page from the federal records, then track down that utility's published contact information and annual Consumer Confidence Report. Even in a city with one well-known source, addresses near boundaries can sit on different public water systems, so confirm which one serves your street rather than assuming the citywide picture.
Much of San Francisco's supply is widely understood to come from the Hetch Hetchy system, originating largely as Sierra Nevada snowmelt stored at high elevation and delivered across the region, with some local and Bay Area supplies in the mix. The exact blend can shift with drought and operations, so this is the broad, well-established picture rather than your exact tap.
Sierra snowmelt-fed supplies across much of the region tend toward the softer end, but hardness is a comfort-and-appliances topic, not a health one, and we won't quote a figure we can't source for your home. To learn your own number, use an inexpensive test strip or check your utility's annual report, which usually lists hardness somewhere.
Enter an address — we'll identify the serving water utility, pull PFAS detections, FEMA flood zone, and nearby Superfund sites, then give you a plain-English A–F grade. $19.99 single, $29.99 two-address bundle.
One-time report. PFAS, water violations, Superfund sites, flood zone, air quality, and a plain-English A–F grade for the address.
More California data: Superfund sites · PFAS in California
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