"Joe" writes:

I just recently noticed a vibrating water pipe under the drywall
ceiling of my partially finished basement. It vibrates when the first
floor toilet is flushed and the kitchen sink turns off. The previous
owner finished the basement and I assume the pipes are leaning directly
against the drywall since the pipes go right along the edge of the
beams in the unfinished part of the basement. Is this a problem? I
don't notice any of the other pipes in the basement vibrating when
water is turned off. Is there a way I can minimize the vibration
without cutting open the cieling?

Sounds consistent with water hammer to me.

First thing to try there is to shut off the main supply valve to the
house, then opening faucets at the highest and lowest point of the
home to restore air to whatever air traps may exist in the plumbing.
In layman's terms, these air traps serve as shock absorbers if you
will, and over time they can fill up with water and cease to be
effective.

Caveat: this will also test whether your main cutoff valves actually
work. Do not apply excessive force a gate valve main cut off if it's
not closing fully. I learned this the hard way, but I do have shiny
new quarter turn ball valves for my main cutoffs now. :-) If your
ground is frozen outside, it may be best to wait to try this all when
it's above freezing.

If this procedure doesn't help, there may be strapping that needs to
be added to secure the pipe in question, or air traps added by a
plumber. But in my own experience, recharging the air traps seems to
fix the problem in many cases.

Best Regards,
--
Todd H.
http://www.toddh.net/