What is this??

Any thoughts on what this drain line off the main drain was used for??


wag RO system that’s disconnected and wasn’t installed correctly in the first place

drains should enter tail pipe not trap arm

Reverse Osmosis discharge drain. Barry is right again. It is on the wrong side of the trap. Who wants poopy smell and sewer gases anywhere near their drinking water; kinda defeats the purpose of an OS system. I wonder if that is why they took out the OS system; “crappy water”.