Related to Can I tap into the kitchen / dishwasher drain pipe with my washing machine?, but not the same.
I want to plumb a dehumidifier into a drain for a bathroom sink on the other side of the wall. I just cut into the wall on the dehumidifier side (looking for a leak; it turned out to not be leaking).
The pipe heading off to the right at the bottom is the sink drain. the P-trap is under the sink, on that far side of the wall. I am not clear what the pipe going up goes to, as there is only attic above (might be AC drain?).
I want to bring a port through the wall, in a way that I can run the dehumidifier discharge hose directly into it. How can I best do that?