Plumbing issue – tub holding water

I have an older 2-story house with with an unfinished basement that houses the utilities.

Over the last month, the tub upstairs is holding water after showering. It starts filling almost immediately when showering. I would guess it takes 15-20 minutes to drain after the water is shut off.

At first, I thought the tub drain was plugged somewhere near the tub.

I’ve tried running a snake through the pipe, but with the tubs location near an exterior wall, the new PVC pipe goes straight down, turns 90 to the right, then enters the P-trap. I have not been able to get the snake passed the P-trap, at least I don’t think I have. After the P-trap, the pipe takes a 90 to the left and connects to the original schedule 40 pipe before dropping down and running to the basement. I am going to try to disconnect the P-trap tonight and check for blockages.

The part that has me wondering if there may be a venting issue is that when the sink upstairs or the sink in the downstairs kitchen are running, the tub will back up. A little bit of water comes up through the drain and then slowly returns. I don’t know how this would be possible if there were a blockage in the pipes leading from the tub.

Any plumbers out there that could shed some light on the problem. I am really hoping to have this fixed by the weekend, so I can fish on Saturday and turkey hunt on Sunday… if you know what I mean. Thanks,

Lars

I am not a plumber by any means but sounds like blockage, we had that happen in our house and instead of snaking now every spring and fall I use my power washer and shoot it down the drains to clean then out good and haven’t had any issues since…good luck!

The fact that it backs up when the kitchen or wpstairs lavatory is used tells me that the blockage is downstream of where they tie together. Both the lav and the kitchen waste lines are higher that the bath waste.

Can you see if a vent is tied onto the tub drain? This should be with in 3′ of the trap if I remember right.

It seems to me like a clogged drain downstream of where they tie together. Look for cleanout plug in vertical pipe where it comes through basement floor up to fixtures with problem. Sometimes using miror and flashlight to see standing water after removing cleanout plug to locate clog helps, might still have water. Lower sink should not be backing up fixtue on floor above? If it were vent issue, it would drain good momentarily then slow down to suck air through water to breathe.