In article , "Walter R." wrote:

After I have installed a new softener, how can I determine which faucets
have soft and which ones have hard water?

There's a simple chemical test which will show the difference clearly. Fill a
quart jar about half-way with distilled water, and dissolve about 1/4 cup of
Epsom salts in it. Then add a cup of the water you want to test. Soft water
will have no noticeable effect, but hard water will instantly turn the
solution cloudy.