the 2nd floor bathroom (sink, toilet, tub), I noticed a flexible hose coming into the sink drain. It's below the counter, above the trap. Both of our AC units is outside downstairs. Can I remove it when i go to put in a new P trap. Our sinks are leaking because of the way it is set up.
Can you remove it? Of course. Might there be consequences of removing it? Probably, but we have no way of knowing. Usually if there is something odd like that, there was a reason for it. You should try harder to ascertain what that "tube" is coming from. Heater condensate drain? Dehumidifier drain? Pot farm in the attic?