I'm looking at possibly moving my washer/dryer to the other side of the basement, but I have a few questions. In addition to moving the laundry, I'd also like to add a lavatory (bar sink) just upstream of the laundry. I have above ground access to a 4inch waste line that runs along the basement floor. However, in order to tie my new line into the current line at this point, I'd have to run the new line (likely 3 inch) just above the old 4 inch line, then drop down to tie into the old waste line. Is this possible? I'd like to know before I waste my time with a permit application and discussion with an inspector. How would they connect? I'm envisioning a 3inch horizontal from the CW and lavatory traps, connecting to a sanitary tee with a cleanout, dropping down to a long sweep 4x3 wye to mate with the 4inch waste line. This is a bit of a complicated path for the waste to follow. Is it legit? If not, how could it be done so it follows code (I live in PA)? This is an old house (1915) and the basement will never be finished. I'm just trying to move the current set-up to a more favorable location. Also, for venting, I have access to a 4inch vertical in the basement that serves as the waste stack for a second floor bathroom set (WC, Lav, Bath/Shower). I'm assuming that I cannot tie into this for venting. I can run a vent line to the attic to tie into this same stack if necessary. I could also use AAVs for the basement lav and washer. For the basement lav, the distance between the trap and potential tie-in is ~30 feet. This line would serve no other fixtures other than the basement lav and CW.