I want to install a sink and toilet in my basement. I have a bathroom directly above. Can I tap into the existing drain without adding vents? The pipe is ABS, can I use PVC with this or do I need to stick with ABS? I have pictures but don't know how to add them. Thanks.

Hi shawnee...

Nope... you can connect into the drain pipe but you will definitely need to install vents for the toilet and the sink. You may be able to eliminate some of the venting requirements IF WET VENTING is allowed in your state (check local plumbing codes)... if not, add a vent to each fixture.

If wet venting is allowed you may be able to pipe this up so the sink vent wet vents the toilet. This option requires that the waste pipes connect together in a very specific manner... :)

In terms of the ABS vs PVC, most likely, if ABS is in your house it is what the local plumbing code requires... stick to ABS.

Back to you...

MARK