09/08/2026
Three words that can add twenty thousand dollars to a bathroom: move the plumbing.
People say it casually. “Can we just shift the toilet over a few feet, put the vanity on that wall instead.” It sounds like rearranging furniture. It isn’t.
A drain doesn’t get slid across the room. It has to fall a quarter inch for every foot it travels to reach the stack — the vertical pipe that carries everything down and out. That fall has to happen inside the depth of your floor joists, and your floor joists are a fixed number of inches deep.
Move a fixture a short distance and you’re fine. Move it far enough that the fall runs out of room, and now you’re furring down the ceiling in the room below, or cutting and reinforcing joists, which is an engineering conversation rather than a plumbing one.
The same six feet is a small change order in one house and a five-figure job in the one next door. What decides it isn’t the distance. It’s where the stack already is — and that was decided when the house was built.
It’s one of the five drivers on our bathroom cost guide, and it’s the one that moves a project between tiers more often than any finish ever will.