How to Install a Bathroom Vanity and Sink

With the main water off, put a fresh shutoff valve on each supply stub coming out of the wall. Josh uses push-to-connect angle stops, so there's no soldering and no compression nut to fuss with. Clean the pipe, mark your insertion depth, then push the valve straight on until it seats.

Do the hot and the cold the same way. A push-to-connect fitting grips the pipe with an internal ring, so once it clicks home it holds pressure on its own.

Slide the trap adapter onto the drain stub-out sticking through the wall. This is the fitting the P-trap will connect to later, so get it seated square and snug now while you have clear access.

Take a second to eyeball both shutoff valves. The handles should sit level and point the same way, and the outlets should aim down and out toward where the supply lines will run. Getting this tidy now makes the final hookup painless.

Slide the cabinet into place over the plumbing, then check it with a level side to side and front to back. Shim under the base if the floor isn't flat so the top will sit true later.

Once it's level, drive screws through the back rail of the cabinet into the wall studs. Find the studs with a stud finder first. Two or three solid screws into framing is what keeps the vanity from rocking every time someone leans on it.

Before you set the top down, mount the faucet while you can still reach the underside easily. Drop the faucet body through the holes in the sink deck and line up the base gasket underneath.

From below, thread on the mounting nuts and snug them by hand, then finish with a wrench. Keep the faucet straight as you tighten so it doesn't drift off-center. Doing this on the bench beats fighting for room inside a mounted cabinet.

Set the drain body into the sink opening and thread the tailpiece up from underneath. There's a rubber gasket and a friction washer that stack in a specific order, so follow the parts diagram that came with the kit.

Run a thin bead of silicone or plumber's putty under the drain flange before you tighten it down. That's what stops water from wicking under the flange and dripping into the cabinet.

Run a braided stainless supply line from each faucet tailpiece down to its shutoff valve. Match hot to hot and cold to cold. The braided lines flex, so you don't have to line anything up perfectly.

Thread each nut on by hand first to avoid cross-threading, then snug with a wrench. Firm is enough here. The rubber washer inside the nut does the sealing, so cranking harder just risks stripping the threads.

Now connect the drain to the waste line. The P-trap ties the sink tailpiece to the trap adapter you set in the wall earlier. Its U-shape holds a plug of water that blocks sewer gas from rising up through the drain.

Dry-fit the pieces first to check the angles, trim the tailpiece if it's too long, then hand-tighten the slip nuts with the plastic washers seated. These joints only need to be hand-snug plus a small nudge.

Here's the finished vanity: cabinet screwed to the wall, top set, faucet mounted, and everything plumbed. Open both shutoff valves slowly and turn the faucet on.

Watch every joint you made. Check the supply-line nuts, the drain flange, and each slip joint on the P-trap. Fill the basin and let it drain to load the trap under real flow. A drip now is easy to fix with a small nudge of the wrench; a drip you miss becomes a swollen cabinet floor in a month.