I am hoping that someone can offer a suggestion to solve my problem. We recently purchased a 60 year old home. The sink in one of our bathrooms drains completely fine until the water has run for about 5 minutes and then all of a sudden it starts to back up and then drains very slowly. I have verified that the trap, etc is completely clear.

My first guess was that there was a partial blockage somewhere down the line, but neither the toilet nor the tub in the same bathroom has any problem at all - and all other drains throughout the house experience no problem. Could this be a venting problem?

The bathroom is on the first floor and I can get into the crawlspace below. I have verified that the sink, tub, etc all ultimately connect to the same main line.

We are on city sewer and the pipes in this part of the house are galvanized - so I am certain that there is at least some corrosion in the pipes.

Thank you.

speedball1

I don't see that you have much choice but to snake out the lavatory roof vent and drain line. Had you said the lav backed up right away I would have suspected a clog in the trap or the arm but your description puts it down the road in the drain line. Drop your snake down to the bend at the base and put out about 15 or 20 feet more. Afterwards flush out the line with hot water. Good luck. Tom

bkpayne

Thanks for the reply. The auger seemed to solve the problem - I assume that the corrosion inside the galvanized pipe had just caught hair, etc somewhere down the pipe and slowed it down considerably.

otis7895

I have the same problem also. I just put in a new vanity and changed the trap and ran a small electrician's snake down the 1 1/4 copper line behind the wall and my new sink starts to back up after a minute of the water running. I made a trap from pvc any chance the trap is too deep????2

massplumber2008

Hello Otis.

Otis this post is over two years old. Re-post your question as a new thread...that will put your question at the TOP of the list....not WAY back here in 2005...

Oh! The electrician's snake is not the way to go here...re-post question so all the pros at askmehelpdesk.com can give an opinion...I am sure we can help you to resolve...give as much information as possible...talk soon.