max drain pipe length

are these drain pipes longer than allowed?
if so, any official requirement to back it up?


Now thats one nasty little set-up. Firstly, I believe it should only have one p-trap per fixture and I think they class a double sink as one fixture. Secondly, I think that set-up could result in drainage/venting problems. I’m sure you’d be safe to say to have a plumber evaluate and correct. :D: Also was it vented??

UPC says this is a no-no, but the IRC allows it.

Under the IRC you may connect two traps to one waste arm however the diameter of that waste arm must be sufficient to handle the combined Drainage Fixture Unit (DFU) load of the two trapped fixtures.

The UPC prohibits two traps connected to a common waste arm. Under the UPC when two back to back sinks are connected to a common vertical riser they must be connect by means of a Sanitary cross (Double sanitary Tee) with a separate waste arm to each fixture.

How about for the length of the drain pipes coming off of the sink?

24" is the maximum allowable length for the tail piece - except for a washing-machine standpipe, which can be 36".

thanks jeff.
i see you posted this in brian v’s tub question.