[Shop-talk] Seasonal water hammer?

[Randall]

---- Larry Spector <lspector at gmail.com> wrote: 
> I've got an odd problem, and it's been going on for a couple of years now.
> Every fall, when the cold water supply (county water) starts getting even
> colder, I get water hammer. I can usually get it to go away by turning off
> the tap and turning it back on slowly, but it's a pain to deal with.

This caught my eye ... "water hammer" is what happens when you turn the water _off_ suddenly.  Your mention of turning it _on_ slowly suggests that you are talking about something else; like perhaps the stem vibration that was already mentioned.

FWIW, there are water hammer arrestors that use a diaphragm or piston to isolate the air cushion; hence they shouldn't require draining, at least not every year.  My experience has been that just mounting the pipes properly eliminates audible water hammer, but YMMV.

Randall