Hello

HELP! My situation is... water backs up into downstairs bathroom sink apparently after the upstairs shower has been used which is directly above the downstairs bathroom. Our house is around 40 years old. We have had people there before and opened up the wall on either side of the downstairs bathroom and replaced the "Y" joining of the pipes, as well as the piping under the sink downstairs about 6 months ago or so.

The problem has just come back. Any clues what IS REALLY causing this again?. HELP!!

Thank you in advance!

Your shower and sink are piped together to the main drain. Your plug is just prior to joining that main or else you'd see a back up into a tub or shower. It is likely hair and body oil. I dfo not normally recommend chemicals but this may be your only option short of opening those walls again.

Hi there. We also have an old house (63 yrs old), with much of the original plumbing. We also get clogs & water backups. The best thing I've found is Liquid Plumber Foaming Pipe Cleaner. Before I go to bed, I pour a bottle into the bathtub, another bottle is split between the bathroom sink and the unused shower stall drain. It's left undisturbed all night. In the morning I flush the tub and all the other drains with hot water. This solves the problem for about a year or so. Since your downstairs bathroom sink is involved, I would dose that with a bottle at the same time, too. Good Luck!

Bob
Why wouldn't you just snake the downstairs bath lavatory drain?

Thank you very much. As you suspected it was clogged. It's an old house the plumber said and this will happen from time to time. I had it "snaked" and all seems good now.

Thanks again.

Clean your drain servicing this run. It is clogged up. No need to open walls

Harold, snaking is usually the way to go but if its just hair a small dose on Liquid Plumber might be quicker. The homeowner seemed to rely on plumbers so I figured he/she wasn't into snaking on their own so I suggested the Liquid Plumber. Turns out they called a plumber from the wording of the last post. I would have snaked the lav drain but sometimes the home owner isn't up to that.