How to Install Bathroom Vanity? | A Straightforward DIY Walkthrough

Installing a bathroom vanity is a DIY job you can finish in a day with basic tools, careful measuring, and a steady hand.

Replacing a bathroom vanity is one of the most rewarding weekend projects for a homeowner. It instantly updates the look of the room and adds real storage. The work itself is straightforward, but skipping prep steps can lead to wobbly cabinets or leaky connections later. This guide walks through the complete process from start to finish. For the best results, take your time with the measuring and leveling steps, as they determine how good the final install looks.

Prepare the Space and Turn Off the Water

Before you touch a wrench, shut off the water supply. Look for the angle-stop valves on the wall behind the vanity, usually two small valves with oval handles. Turn them clockwise until they stop, then open the faucet on the old sink to relieve any pressure left in the lines.

The next phase is removal. Disconnect the drain P-trap and the supply lines from the shut-off valves. Have a bucket and rags ready because water will still sit in the P-trap. Run a utility knife along the caulk line where the old vanity meets the wall, then look for the screws or brackets holding it in place. Once those are out, the entire unit should pull free from the wall. Removing the cabinet doors first can make the old vanity lighter and easier to move, a tip Lowe’s installation guide recommends.

Measure, Mark, and Set the New Cabinet

With the old vanity gone, measure the new cabinet’s width and height to confirm it will fit in the space. Map out the new location on the wall and run a stud finder across the area to locate the framing. Mark each stud’s center with a pencil so you know exactly where to secure the vanity.

Slide the new cabinet into position, making sure it sits flush against the wall. Use a level on top of the cabinet and check both front-to-back and side-to-side. Floors are rarely perfectly flat, so you’ll likely need wood shims under the cabinet’s base to get it true. Once level, drill pilot holes through the cabinet’s back panel and into the studs, then drive screws to lock it in place. Home Depot’s guide recommends 3-inch drywall screws for this job. If the vanity is narrow and the holes don’t align with a stud, use wall anchors sized for your wall type to get a more secure install. For wall-mounted vanities, remember that the leveling bracket is just for leveling — permanent support has to come from lag bolts driven into the wall’s wood backing or studs per Lowe’s manual.

If you haven’t picked the right cabinet yet, a well-built unit makes installation easier. A roundup of the best 30 inch wood bathroom vanity options can help narrow the choice before you start.

Connect the Plumbing and Install the Top

The plumbing hookup is the part that rewards patience. Set the vanity top (with the sink bowl and faucet already mounted) into place, following the manufacturer’s guidance for your specific model. The faucet hole pattern and drain connection vary between products, so always check the included instructions.

Reconnect the water supply lines to the shut-off valves and hand-tighten them first, then snug them with a wrench — over-tightening can crack the nuts. Attach the drain P-trap, making sure the slip nuts have fresh washers. Once everything is connected, turn the water back on slowly and check every joint for drips. Run water through both the hot and cold taps to confirm a steady flow and to test the drain. A leak here means you should tighten gently or re-seat the connection rather than move on.

Finish by running a thin bead of silicone caulk along the back edge where the vanity meets the wall and where the backsplash meets the counter. Smooth it with a wet finger and wipe away excess for a clean, professional look.

When to Call a Professional

The DIY path works well if the plumbing aligns and your wall structure is solid. There are situations where it’s smarter to hand the job off. If the open wall exposes rotted framing or water damage, or if the plumbing stubs don’t line up with the new cabinet’s cutouts, a licensed plumber or installer is the right call. Lowe’s offers professional bathroom installation services, and Home Depot does for many vanity-with-top products as well. You need a pro when the job crosses from “fiddly” into “structural,” because a cabinet that isn’t anchored to the wall is a safety hazard, not just an eyesore.