It's not clear from your post why you want to filter your water. Is your
well water dirty ( small particles )? If so a filter between the well and
the softener may help. Check with a local plumber or your neighbors for
filters that work on the local water.
The humidifier should be cleaned and maintained on a regular basis.
Softened water will leave salt in it as it evaporates. This must be removed.
I believe that the " pad " (the lattice) should be replaced occasionally.
Get an owner's manual for the humidifier.
Water heaters are not usually drained for cleaning. Normally the drain
valve is opened and the water is run out for several minutes ( or until crud
stops coming out ). It is possible for the drain valve to fail while doing
this but drain valve replacement is usually a cheap and easy DIY project.


Dave,

I don't know that I need one, I am just preparing for it in case we do (we are
not in the house yet).

Thanks for the reply and the info.