Why is my upstairs sink draining into my downstairs bathtub and sink?

Hey Maureen:

Is this upstairs sink at the first floor and the downstairs bathtub and sink in the basement?

If so, sounds like common drain line clogged or even maybe the main drain line... *frown*... let's hope for better news.. ok?

Let us know where fixtures are located... and if any other fixtures are causing issues (check by flushing toilets, running other sinks, etc.)

Also, city/town sewer or septic..

Talk soon... Mark

Maureen, picture your plumbing like a tree trunk with branches. The branch tips are your fixtures like sinks and tubs, the trunk is the sewer main. If a branch is plugged before it reaches the trunk then all fixture on that branch and smaller branches will back up, they will come out of the drains of fixture lower than you upstairs sink. Try to answer Mark's qusetions and do you feel like you can do the rodding necessary? If you have no tools, no experience and aren't in a position to try this then just call a licensed plumber.