How to Install a Bathroom Vanity: DIY Step-by-Step Guide

Replacing an old vanity is one of the most rewarding bathroom upgrades a homeowner can tackle on a weekend. If you've been wondering how to install a bathroom vanity without hiring a contractor, the good news is that with the right tools, a few hours, and this walkthrough, it's completely doable. This guide covers every stage — removing the old unit, prepping the space, connecting the plumbing, and securing the new cabinet and countertop — so you can finish the job confidently and correctly.

Tools and Materials You'll Need

Before you touch a single pipe, gather everything on this list. Running to the hardware store mid-project wastes time and can leave your bathroom out of commission overnight.

• Adjustable wrench and basin wrench
• Pipe wrench
• Drill and drill bits (including a masonry bit if your walls are tile or concrete)
• Stud finder
• Level (4-foot is ideal)
• Utility knife and putty knife
• Measuring tape
• Bucket and towels (for residual water)
• Plumber's putty or silicone caulk
• Teflon (plumber's) tape
• Wood shims
• Lag screws or mounting hardware (often included with the vanity)
• P-trap kit and supply lines (if not already included)

Check your new vanity's instruction sheet before buying extra hardware — many single bathroom vanities ship with mounting brackets and drain assemblies already in the box.

Step 1 — Shut Off the Water and Disconnect Plumbing

Safety first: turn off the hot and cold supply valves under the existing sink. If there are no local shutoffs, turn off the main water supply to the house. Open the faucet to release pressure and drain any water in the lines.

• Place a bucket under the P-trap before loosening the slip-joint nuts — there will be standing water.
• Disconnect the supply lines from the shutoff valves and the faucet tailpieces.
• Unscrew the P-trap slip nuts (hand-tight first, then wrench if needed) and remove the trap.
• If the drain stopper linkage is attached to the faucet body, disconnect it now.

Set the P-trap aside; you may be able to reuse it if it's in good condition and the new drain location matches.

Step 2 — Remove the Old Vanity

With plumbing disconnected, the cabinet itself is usually easier to remove than people expect.

• Cut the caulk bead along the wall and countertop edges with a utility knife. Don't skip this — forcing the cabinet away from the wall without cutting caulk can tear drywall.
• Open the cabinet doors and look inside for screws driven into the wall studs. Remove them.
• If the countertop is separate (common on drop-in sink setups), lift it straight up. It may also be caulked down — cut and wiggle it free.
• Slide the cabinet away from the wall. Have a helper if the unit is heavy or if it's a double bathroom vanity.

Inspect the wall and floor once the old vanity is out. Look for water damage, soft drywall, or mold. Repair anything you find before proceeding — installing a new vanity over damaged substrate will cause problems down the road.

Step 3 — Prepare the Space

This step is where precision pays off.

• Mark stud locations. Use your stud finder and mark every stud in the installation area with a pencil. Most vanities are secured to at least two studs.
• Check the floor level. Set your level on the floor where the cabinet will sit. Note which direction — and how much — the floor slopes. You'll correct this with shims.
• Confirm rough-in dimensions. Measure the distance from the wall to the center of the drain pipe and the center of each supply stub-out. Compare these numbers to your new vanity's cutout template. A mismatch here means you'll need to adjust the plumbing before the cabinet goes in.
• Patch and prime the wall if needed so the new vanity has a clean surface to sit against.

How to Install the Bathroom Vanity Cabinet

Now the fun part. Slide the new cabinet into position — but don't push it all the way against the wall yet. You need clearance to thread supply lines and connect the drain.

• Feed the supply stub-outs and drain pipe through the corresponding holes in the back or bottom of the cabinet.
• Push the cabinet against the wall and check for level side-to-side and front-to-back. Insert shims under the base as needed until it's perfectly level. This matters: an unlevel cabinet causes doors and drawers to swing open or refuse to stay closed.
• Open the cabinet doors and locate the wall studs through the back panel. Pre-drill pilot holes to avoid splitting, then drive lag screws through the cabinet's mounting rail into each stud. Two screws minimum; three or four is better for a heavy unit.
• Score and snap off any shim material that sticks out past the cabinet base with a utility knife or oscillating tool.

Browsing for the right size? HomeBeyond carries vanities across every standard dimension — from compact 24-inch single sink vanities to spacious 61–72-inch double sink models — so you can match your rough-in space exactly.

Step 5 — Install the Faucet and Drain Before Setting the Top

If your vanity comes with a separate countertop or an undermount sink, install the faucet and drain assembly before the top goes on. Working from underneath is far easier on a countertop sitting on a workbench than inside a mounted cabinet.

• Apply plumber's putty or the gasket supplied with the faucet around the faucet base, then drop it through the deck holes and hand-tighten the mounting nut from below.
• Install the drain body: apply putty or silicone under the flange, insert it into the drain hole, and tighten the locknut from below. Wipe away excess putty.
• Attach the pop-up stopper rod and linkage according to the faucet instructions.

If the vanity includes an integrated sink-and-top unit, the faucet and drain may already be pre-drilled and partially assembled — read the documentation that came with your unit.

Step 6 — Set the Countertop and Connect Plumbing

Lower the countertop onto the cabinet. Apply a thin bead of silicone caulk along the top edge of the cabinet first if the manufacturer recommends it. Press the top down firmly and check that it sits flat with no rocking.

Now connect the plumbing:

• Supply lines: Hand-thread the supply lines onto the shutoff valves and the faucet tailpieces. Snug with a wrench — do not overtighten braided stainless lines, as this can crack the fittings.
• P-trap: Slide the trap arm into the drain stub-out in the wall, connect the curved trap section to the drain tailpiece, and tighten all slip nuts. Finger-tight plus a quarter-turn with a wrench is enough for plastic slip-joint fittings.
• Drain tailpiece length: If the tailpiece is too long, cut it with a hacksaw. If it's too short, purchase a longer one or an extension.

Step 7 — Test for Leaks and Finish Up

Turn the supply valves back on slowly. Let the faucet run for two full minutes while you crouch down and inspect every connection — supply lines at both ends, the drain flange, the P-trap slip nuts, and the trap arm where it enters the wall.

• Dry any test water, then check again after five minutes to catch slow seeps.
• Test the drain stopper operation. Adjust the pivot rod clip position if the stopper doesn't fully open or close.
• Once you're satisfied there are no leaks, caulk the seam where the countertop meets the wall and where the cabinet base meets the floor. Smooth with a wet fingertip and let it cure per the caulk manufacturer's instructions (usually 24 hours before water contact).
• Hang your mirror. An LED mirror above the vanity adds both function and style, and many models install with simple toggle bolts or a French cleat.

Frequently Asked Questions

Do I need a permit to replace a bathroom vanity?

In most US jurisdictions, a straight like-for-like vanity replacement that doesn't move drain or supply lines does not require a permit. However, rules vary by county and city. If you're relocating plumbing or doing any electrical work — such as adding a GFCI outlet or new lighting — check with your local building department before starting.

What is the standard height for a bathroom vanity?

Traditional vanity height is 32 inches from floor to countertop. Comfort-height or ADA-compliant vanities measure 36 inches, which is easier on the back for taller adults. Measure from your finished floor to the existing drain stub-out center before buying — most vanities are designed with a standard rough-in range, but confirming this avoids surprises.

Can I install a bathroom vanity on a tile floor without damaging the tile?

Yes. Slide the cabinet into place without dragging it — use furniture sliders or lay a moving blanket on the tile first. Secure the vanity by screwing into wall studs rather than the floor. If you caulk the base to the tile, use a paintable silicone so future removal is cleaner. Avoid drilling into tile at the floor unless your installation specifically requires it.

Ready to find the right fit for your bathroom? Browse the full selection of bathroom vanities and cabinets at HomeBeyond to find a style and size that works perfectly for your space.