ours always gets clog between the drain and the trap. Hot water is good but found this thing recently that does a good job. For $2.50 it's worth a shot.»www.homedepot.com/webapp/wcs/sto···5735-_-x
Got one of those last year; it's cheap enough. And, it worked to clear out a bathroom sink; not so good in the bathtub drain, but it did finally get things started.