View Full Version : anyone ever seen 2 vent pipes under sink?

09-16-2005, 11:01 AM
I'm finishing out a new house and finishing out plumbing myself. The plumber who roughed it in has retired and I'm not sure what is going on under 2 of my sinks. I have my hold cold supply as normal then 2 PVC drain pipes coming out of drywall :confused: ? I'm used to seeing only 1 :) Not sure which one to cement my p-trap to...was this meant for some type of studor vent. If so how do I hook it up...P-trap on left and studor vent on right? I hate to open up the drywall to investigate but it looks like I may have to.


09-16-2005, 11:12 AM
without knowing what is in the walls, and without being able to look into the openings, it is impossible to say what the idea was. If they are side by side, however it is not likely to be for a Studor vent which would normally be above the drain opening.

09-16-2005, 01:00 PM
I'm a little suprised that you're plumber retired in the middle of a job! I would imagine he/she could answer you're question over a simple phone call...if not how about the local plumbing inspector that inspected the work.

09-16-2005, 05:28 PM
Is it just possible that you have two drain lines for a double sink? It is fairly common to run one line, but two isn't a bad idea either, especially if one has a disposer. My unprofessional opinion.

09-17-2005, 05:38 AM
there,s been a few jobs we,ve all retired on haven,t we ?

we just used different words at the time :D

09-17-2005, 07:04 AM
And a lot of them were directed toward the customer.

master plumber mark
09-17-2005, 07:32 AM
its either a loop vent or a vent from above that is
supposed to be tied in during the install under the sink

the best way to figure out which line to tie in your
drain to is to simply flush a couple of toilets in the house

and simply listen to the open pipes under the
sink for the sound of rushing water....

it should be loudest from the main drain line side

and if you are really lucky, as an extra bonus
you might even get
an ooooohhh --soooo --pleasent smell --blast back into your face
while doing this experiment....

09-17-2005, 11:27 AM
Can you not ask this retired plumber what the plan was? If you're on speaking terms, ask him to refresh his memory and let you know... ;)