I have removed a tub and I want to cap the drain line under the floor.
It is in a manufactured home. The drain line will be cut off below the
Floor and is horizontal. Line is 1.5 in. Can I just glue on a cap?

Hi Dingle.

If you have an 1.5" PVC (white plastic) or ABS (black plastic) drain pipe then you sure can cap it. Just be sure to purchase a PVC (or ABS) PRESSURE CAP and not a test cap (thin plastic) or jim cap (neoprene cap).

Mark