Are you sure the clog is not simply in the piping directly
beneath the vanity top?

The plastic (PVC etc.) is typically very easy to disassemble
and then thoroughly clean. Just put a pan beneath it while
you work, to catch the water in the piping "trap," and put a
reminder note or similar at the faucet handles, so as not to
turn them on while you have things apart.

rob wrote
Looks like most of my interior plumbing is pvc piping and
wonder if
its safe to use a little bleach for a bathroom sink to
loosen a clog?
It drains but slowly. I'll probably try a plunger first
regardless
but I've been meaning to ask if the bleach is safe for
interior
plumbing? My house was built in the late 90's if that
matters.
thanks.