Water treatment is the part of plumbing with the most oversold equipment in it,
so our approach starts by working out whether you need anything at all.
The Bay Area is unusually split on this. Homes supplied from Hetch Hetchy get
water that is already soft — installing a softener there solves a problem you
don’t have. Parts of the South Bay drawing on groundwater run considerably
harder, and there the scale genuinely does shorten the life of your water heater
and leave deposits on every fixture. Same county, different answer.
So we look at what your supply actually is before recommending equipment. From
there the job is usually one of three things:
Softening for genuine hardness — sized to the household’s water use, plumbed
with a bypass so the system can be serviced or taken offline without cutting
water to the house.
Whole-house filtration for taste, odour, sediment or chloramine. A carbon
system handles the disinfectant taste most people are actually complaining
about, and it’s a far smaller job than a full treatment install.
Reverse osmosis at the kitchen sink for drinking and cooking. The most
thorough option for dissolved contaminants, and correctly limited to the tap you
actually drink from.
All of it gets installed with proper bypass and isolation valves, so servicing
it later doesn’t mean shutting down the house. That sounds obvious and it’s
routinely skipped — we’ve replaced a lot of systems that were plumbed straight
in with no way to isolate them.