View Full Version : New Washer Hookup

05-16-2011, 08:34 AM
I have a plumber doing various minor upgrades in my house. We are about to start on the largest part of the work (running piping for a new washing machine). The washer will be located in a room directly above the kitchen. The plumber is proposing to tap into the hot & cold copper supply lines at the kitchen sink to run them straight up to the laundry room. The problem is the waste and vent situation.

The 2" waste for the kitchen sink vents straight up through the roof passing through the laundry room on the 2nd floor. The plumber has proposed two scenarios:

#1: Tap into the vent on the second floor for the waste line from the washer, which would be wet venting the kitchen sink below (not ideal).

#2: Run a new waste line for the washer down to the kitchen and tap into the waste line below the kitchen sink P-trap.

The question is: I know option #2 is better than wet venting the sink. In either scenario, the washer will share a vent line with the kitchen sink. Running a new dedicated vent is not an option, as it will have to pass through another apartment above. If we go with option 2, how far beneath the kitchen sink p-trap should the connection be for the waste line?

05-16-2011, 09:22 AM
#2 is the ONLY proper installation. The vent can tie back to the sink vent about 48" above the floor, and into the sink drain almost anywhere below the sink connection, although the further the better.

05-16-2011, 09:47 AM
Once a pipe becomes a drain, it is no longer a vent. But, if you can run a new vent line between the two floors you have access to, you can tie in above the WM drain, and maintain proper venting.