[jlccc]

I have to run new drain pipes for a toilet and sink installation. The sink has white (PVC) drain pipes and the toilet has black (ABS) pipes going into what I believe to be the sewer drain. Can I just connect the white to the black with a tee to drain the sink water? Do I need to vent the sink separately, or will the vent for the toilet be enough.

[Milo Dolezal]

Well, it depends where you are located. In my area, every plumbing fixtures has to have its own vent. In other areas, you can get away with AAV (surface-mounted vent attachment) installed behind the trap and under the sink. You should call your Inspector and ask him what are the Code vent requirements.

To join ABS (black) and PVC (white) plastic pipes you can either use PVC-to-ABS glue or you can use shielded coupling to connect the two.

[ballengerb1]

Rule of thumb, if it drains it needs a trap, if it has a trap it needs a vent.

[massplumber2008]

Jlccc...

I see that these guys covered the venting.

I will answer about the different pipe types you asked about. You cannot join ABS to PVC by just cementing them together. You need to use a SHIELDED TRANSITION CLAMP (see picture) to go between the different plastics and then run either PVC or ABS from the clamp. You will need a plastic to plastic shielded clamp.

Be sure to use either a multi.purpose cement and primer or use the specific cements/primers for each pipe type. But be clear that you cannot cement PVC to ABS using the multi. Purpose cement... can only cement PVC to PVC and ABS to ABS... ok?

Let me know if have questions...

MARK