I'm installing a wet bar in my basement and am tieing the drain line into an existing 2" drain coming from upstairs. Is there a maximum distance I can run the drain line horizontally before joining the vertical drain coming from upstairs? I know it has to drop 1/4" every lin. ft. I need to go about 10 to 12 ft.

Also, can I run the vent line straight up and then turn and run just under the floor joists straight to where the vent for the bathroom vanity is on a perpendicular wall. I will be installing a drop ceiling in this part of the basement so the vent pipe will not be visible.

Does the vent line require a slope? I wouldn't think so but thought I'd ask.

Hi Dave:

Distance you are suggesting... 10-12 ft. no problem at all... just keep the 1/4" ft. and is fine (install a cleanout at every change of direction and just prior to connecting into drain line (called a dandy cleanout or test tee).

You can run straight up just under floor joists...BUT the vent must pitch back toward the sink (1/8" to the ft. will be fine) from the bathroom vanity vent.