Give your posting a better title and you'll get more help.
I AGREE 110%......How can the OP NOT know where da hell it's going to, or coming from???
Due to the fact that it's going into a "drain" tube, and there's a floor drain, it looks like a clothes washer drain line????
I think I'd try removing the end that goes into the white tube, and dropping a weight on a string to see if it contacts
water....and go from there. If YOU, the OP, duzzn't know shidt from shinola in this scenario, then I'd find someone
that does!!