I recently renovated a bathroom, but left the old plumbing in place, and simply reattached to the new tub. The drain system is such that the tub and sink both run towards the stack on same pipeline with the tub furthest away (maybe 10 feet total length, with two 90 degree bends).

Before the reno, the draining seemed fine. Now, it probably takes 3 minutes to drain a quarter full tub! I assume its clogged and should get a snake, but I was wondering if there might be some other issue? Another clue is that sometimes when I run a lot of water in the sink, there is a gargling sound coming from the tub drain.

Anyway, thought id see what answers I can get... thanks.

The drain system is such that the tub and sink both run towards the stack on same pipeline with the tub furthest away (maybe 10 feet total length, with two 90 degree bends).
Another clue is that sometimes when I run a lot of water in the sink, there is a gargling sound coming from the tub drain.
The two 90's will slow the drainage down and encorage clogs. The gurgling sound from the tub tells me that the tub's venting out of the tub waste and that the lavatory vent's clogged. Rent a sewer machine,(see image) and snake from the lavatory roof vent. Put out enough cable to reach the base and 16feet more. Good luck and thank you for rating my answer. Tom

Makes sense, except there is no 'lavatory vent'. Its an old house, and the whole bath plumbing is just vented off the main stack (into which the pipe runs from the tub and sink drains). The stack is vertical 4" cast iron, so I don't see how that could be clogged. Isn't it more likely that there is a clog in the pipe down stream from the sink? Hence, that's why the sink tries to vent through the tub drain...

If I'm right, how would I unclog this? Snake from the sink drain?

there is no 'lavatory vent'. Its an old house, and the whole bath plumbing is just vented off the main stack (into which the pipe runs from the tub and sink drains). The stack is vertical 4" cast iron, so I don't see how that could be clogged. Isn't it more likely that there is a clog in the pipe down stream from the sink? Hence, that's why the sink tries to vent through the tub drain...
You don't have a clog or a drainage problem. You sink's venting through the tub waste because it has nowhere else to vent. Install a AAV( Air Admittance Vent) just dowstream of the lavatory trap and ree if that doesn't solfe the problem. Good luck, Tom

You don't have a clog or a drainage problem. You sink's venting through the tub waste because it has nowhere else to vent. Install a AAV( Air Admittance Vent) just dowstream of the lavatory trap and ree if that doesn't solfe the problem. good luck, Tom


Cool thanks for the follow up.

Another quick question: what if I installed an AAV, or even an actual vent downstream from the tub but upstream from the lavatory, would that solve the problem, or help? (its logistically much easier to do this for my bathroom setup)

I don't quite understand the venting process... but is the idea that air has to come in behind the draining water to allow it to flow quickly?

The Image below may help you, good luck.

John

The Image below may help you, good luck.

John

I need x-ray vision to see that tiny pic.

and an AAV won't work on my pedestal sink... not enough room.

You have not mention any where that you have a pedestal sink, I just wanted you to see how the AAV can be installed.

If you want to fix your problem you need to install a vent some where, follow Tom's instructions he it the master, good luck.

John

another quick question: what if I installed an AAV, or even an actual vent downstream from the tub but upstream from the lavatory, would that solve the problem, or help? (its logistically much easier to do this for my bathroom setup) This is a "S" trap,(see image) If any bof your fixture traps look like this the fixture's unvented. "S" traps are outlawed and against code. How many do you have? Regards, Tom