I am installing a new shower in an upstairs attic. I am taking part of a downstairs closet for a chase wall to run the plumbing and electrical. The closet is 10' from where the shower drain will be located. Rather than pull up good hardwood floor or tear out a plaster ceiling, I plan to push the drain line under the floor from the attic space near the closet. I would like to locate the trap in the closet as that would be easier than pushing the trap assembly the 10' to the shower; not to mention that I am limited in the space between the floor and ceiling below.
- If a 3" pipe is run to a 2" trap the pipe is sufficiently oversized to be considered self venting.
- A running trap may be used remotely which uses less space at the shower drain.
- To answer the original question, I don't know the distance to trap max but it depends on the piping size.