Scouting for space. Consider under stairs, closets, and stealing space from other areas, such as bedroom alcoves and porches. A space about 3-by-6-feet or 4-by-5 feet will work.

Stay connected. The farther away connections to existing plumbing pipes and exhaust vent stacks are, the costlier the project. It’s easier and cheaper to run lines through an unfinished area above or below a bath than a finished area you have to cut into and then re-patch.

Look for space near existing “water walls”—walls that already have plumbing in them, usually located in kitchens and existing bathrooms.

Don’t sweat the windows. No need for windows in your small bath—they’ll just eat up valuable wall space. Instead, install shelves for hand towels and soaps.

The doors. If codes allow and you have the space, have your door swing inward to avoid collisions. Better yet, consider a pocket door that glides into a wall and saves space inside the bath and out.

Small is beautiful. Lilliputian fixtures offer high style for small spaces. The general idea: Pedestal sinks, wall-wide mirrors to enlarge tiny spaces, light colors, wall-mounted sinks and faucets, and shelves.

  • Kohler claims its Rialto toilet, at 25.25 inches front to back, is the industry’s smallest. Cost: About $300.
  • The Whitehaus Isabella wall-mounted sink (WH114RTB) is a mere 20 inches wide and 10 inches deep. Cost: About $250.

By the book. A bathroom project require permits and an inspection to ensure it meets codes. Otherwise, you could be forced to tear out whatever wasn’t done right.