It sounds like maybe you have a pipe obsruction.. maybe use a cheap plumbing
snake available from Lowe's Home Depot, or even walmart, to see if there's
anything in there?

They always come in handy sooner or later for your home anyway, and are much
better on your pipes and septic systems then chemical clog solutions.

Might be a quick 5 minute clear?

--
Gareee
(Gary Tabar Jr.)