Installing a New Bathroom Vanity and Sink

Preparation and Measurement

Measure the existing vanity dimensions (width, depth, height) and the rough-in locations of the water supply lines and drain pipe. New vanities must accommodate these existing connections or you will need to modify the plumbing. Standard vanity heights are 30 to 36 inches; comfort-height vanities (36 inches) are increasingly popular. Measure the distance from the wall to the center of the drain pipe and the height of the supply valves — the new vanity must provide clearance for all connections.

Removing the Old Vanity

Turn off the water supply valves and disconnect the supply lines from the faucet. Place a bucket under the P-trap and disconnect it. If the vanity has a backsplash caulked to the wall, cut the caulk with a utility knife. Remove the screws holding the vanity to the wall (usually accessible from inside the cabinet). Lift the vanity and countertop out — they may be quite heavy if made of stone or solid surface. Check the wall and floor for water damage that should be repaired before installing the new vanity.

Installing the New Vanity

Position the new vanity against the wall and check for level using a bubble level on the countertop. Shim under the base if needed to achieve level. Mark and drill pilot holes through the cabinet back into wall studs. Secure the vanity with screws driven into at least two wall studs. Install the sink and faucet on the countertop before mounting it on the vanity — working on the countertop is much easier when it is on the floor or a work surface rather than installed against the wall.

Making Plumbing Connections

Mount the faucet and drain assembly according to their instructions. Set the countertop on the vanity and secure it per manufacturer guidelines. Connect the supply lines from the shut-off valves to the faucet tailpieces using braided stainless steel supply lines. Assemble the P-trap connecting the sink drain to the wall drain pipe — use slip joints for adjustability. Hand-tighten all slip nuts plus a quarter turn with pliers. Turn on the water supply, check for leaks at every connection, and test both hot and cold water. Run water for several minutes while checking under the vanity with a flashlight.