How far can the p-trap be away from the sink drain? I heard 24" but what if I broke up the fall using two 45s

Question

I have to install the drain for a pedestal sink through the floor. I have no room to install a traditional ptrap setup so I wanted to install the ptrap under the floor. I heard 24" was the max drop from drain to ptrap but what if I broke up the fall with 2 45s? Would that make a difference at all? I have about 30 inches to drop before I can install the p-trap under the floor.

Answer 1

As your in inches you are probably Stateside. You need to clear this for building codes - putting in unnecessary steps sounds a recipe for disaster.

Answer 2

I never heard of a certain distance the trap had to be to the sink .........I'm sure u can put it under the floor....if your thinking of using two 45 degree elbows instead of using a trap then u can not do that....the trap holds water inside to  stop sewer gas from entering the house

Answer 3

if you install the p trap that deep, you may have issues with the water not having enough hydraulic pressure to move through the system well.

Check your local codes

Answer 4

That's a building code issue. You will have to check with your state's code department.  Off the top of my head, however, I wouldn't put any bends between the sink and the P trap, because you want the P trap to serve as the cleanout.  If you have bends between it and the sink, you're going be looking at some gnarly clog-removal in the future.

Answer 5

The standard plumbing codes states that the trap must not be more then 24 inches from the fixture outlet. Adding 2 - 45's will not make it pass code.

Usually when you are installing this type of fixture and your drain connection is under the floor, you would install the trap and then put a 180 degree bend imediately after the trap to direct it back down to the floor. You can then add 45's if needed to meet up with your drain pipe connection.