I'm trying to sell a condo, ground floor, heat pump, furnace is in a closet, condensate line drops into drain pipe which hooks into the sink drain in the bathroom. Home Inspector says it drains into waste water line, needs a trap installed. Condo assoc never heard of such a thing, what's the scoop on it? Anybody know?

condensate line drops into drain pipe which hooks into the sink drain in the bathroom Please give us more details. Does it hook directly into the sink drain? Does it connect above the trap? Into a open pipe? What? Please explain. Tom

Condensate line itself sits in an open pipe (L shape) the straight portion of that pipe goes into the sink drain pipe approx 3" beyond the trap

No wonder the inspector was concerned. You have just described a direct opening to the sewer allowing sewer gas to enter your unit. That open line MUST have a trap and a short raiser installed. The condensate line should terminate in a elbo a few inhes above the raiser. This is called a indirect waste. Good luck, Tom

It's never a good idea to drain condensate into the sewer system and in most localities, it's illegal. The trap almost never stays full and because of that sewer gas is brought into the building when the AC or heat pump runs. This created LOTS of problems at my place of work when they did that. Eye infections and smells. I'm still suffering from it when an HMO failed to treat my eye properly.

Thank you. It does terminate in an elbow a few inches above the rasier.

Minnie525: in my area of operation the condensation line has to be connected to a Trapped Fixture ( like sink ) via Branch "T" and Before the Trap itself. The condensation line itself has to have its own trap. I think this is what Inspector requires. See the sketch...

Thank you. It does terminate in an elbow a few inches above the rasier.

But the raiser must be trapped. Milo shows the trap connected to the tailpiece but I believe you show the AC line connected to the stubout "downstream" from the lavatory trap. With Milos drawing connecting above the lavatory trap a trap on the AC line wouldn't be needed becaise it's already trapped but that's not the case here. KISS came out with some valid concerns about the trap seal drying up durning the heating season.
To remedy that I like Milos idea better then my "indirect waste". Make the system a closed one and connect directly to the raiser. However I can see no advantage in double trapping the AC line if you use a branch tailpiece and reconnect the AC line above the trap. Good luck, Tom. Regards, Tom

Trapping the heat pump/AC condensation line prevents blowing hot or cool air into the drain. Energy conservation.