A gut renovation of a bathroom is going to cost some serious cash no matter what—there's the requisite plumbing and electric work, the new tile, the fresh coat of paint—but there's one update that could send you over budget in a blink, and it's completely avoidable. We're talking about moving things around. Rearranging the layout of the sink, shower, or toilet (or all three) will most likely double, and in some cases triple, your plumbing costs, says Nick Schiffer, owner of NS Builders.
The price comes down to two things: the expected costs and the surprise costs. Toilets, sinks, and showers will always require pipes that wind through the house to connect to vent, water, and drain lines. The farther away you move these fixtures from those lines, the more complicated it gets and the longer it will take. "A lot of the work is under-floor work: pulling up the subfloor and reworking the plumbing in between the floor joists," Schiffer explains. "It’s generally more expensive because you’re adding additional time for the plumber to be on site and additional materials." He estimates you'll need a plumber for a day and a half if you're not moving things, versus three to five days if you are—and, FYI, you'll be paying the plumber hourly.
Then there are the issues that could pop up mid-renovation. Perhaps your plumbing isn't up to code (a common issue in old houses) and needs to be replaced entirely, or the floor joists in the toilet's new spot go in the wrong direction, which will require an engineer to come in and figure out how to get it done. There goes more money.
Of course, we're saying your plumbing budget will probably rather than definitely go up because you could get really, really lucky. According to Schiffer, the increase in cost will be less drastic "if you open the walls up and everything works in your favor: The water lines are the right size, the vent stacks are within reach of code, the waste lines can all be rerouted in an easy manner. All the stars have to align to where you’re not modifying anything, you’re strictly running new pipe and that’s it." The decision, or should we say gamble, is up to you.