Water Reports / CA
San Francisco tap water, decoded.
Source: San Francisco Public Utilities Commission
Disinfectant
Chloramine
Hardness
Very soft
TDS
40–90 ppm
Watch items
3
What to know about San Francisco water
- +Chloramine system-wide, persistent to the tap, despite the famously pristine Hetch Hetchy source.
- +Source water is snowmelt from Yosemite, so mineral content is very low, which some palates read as flat.
- +Occasional earthy notes when the system blends in local reservoir water.
Hardness detail: ~1–2 grains per gallon.
For your shower
Soft water is kind to skin and hair on its own, so the job here is purely chemical: chloramine. Catalytic carbon with real contact time handles it; scale is a non-issue.
For your glass
Hetch Hetchy water is about as clean as municipal water gets. The chloramine is the one thing between you and mountain snowmelt, and once it is reduced, the remaining question is taste preference: some people add minerals back for structure.
How we'd filter San Francisco
San Francisco is the terroir use case in miniature. The supply is so pure that remineralization is less about fixing anything and more about choosing your water's character, soft and sweet like Izumi or structured like Alpin Dolomit.
Is San Francisco tap water really that clean?
The source is: Hetch Hetchy delivers snowmelt that requires minimal treatment. The one caveat is chloramine, added for distribution stability, which reaches your tap intact and benefits from catalytic carbon reduction.
Why does SF use chloramine on such clean water?
Stability. Even pristine water picks up biology across miles of distribution pipes, and chloramine stays active far longer than chlorine. It is the right call for the utility, and an easy one to address at home.
Why does my water taste flat in SF?
Very low mineral content. Water with under 100 ppm TDS reads as soft and slightly empty to some palates. Remineralization, which is taste rather than safety, is the fix if you want more structure.
More reports
Figures are drawn from each utility's most recent consumer confidence report and public statements. Water chemistry varies by season and neighborhood; your utility's annual report is the authoritative source for your address.