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How to Install a Bathroom Vanity

Home/Resources/Bathroom/Installing a Bathroom Vanity
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Written & researched by Priya Anand DIY & Tools Editor
Updated August 2026
Low-angle view of a person's hands fitting a new shower head in a tiled bathroom, in warm evening lamplight

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Installing a bathroom vanity is a moderate DIY project most confident homeowners can finish in about half a day, provided the drain and water supply stub-outs are already in the wall. Budget roughly $150 to $600 for the vanity and top, plus $30 or so in supply lines, a P-trap, shims and silicone. The cabinet-setting and top-mounting is straightforward carpentry. The only part touching code is the plumbing connection, and reconnecting to existing shut-off valves is DIY-friendly; moving or adding drain and supply lines is a licensed-plumber job in most jurisdictions.

How To Install A Bathroom Vanity (Lowe's Home Improvement)

Step-by-step: setting and plumbing a vanity

This covers a standard cabinet-style vanity replacing an old one, with existing plumbing in the wall.

  1. Shut off the water and remove the old vanity. Close both shut-off valves under the sink, open the faucet to drain the lines, and disconnect the supply lines and P-trap into a bucket. Cut any caulk bead along the wall and top with a utility knife, then unscrew the cabinet from the wall and lift it out.
  2. Mark your studs and the finished vanity height. Find studs with a magnetic or electronic finder and mark them above the vanity line. Measure up from the floor to your chosen counter height, commonly 34 to 36 inches for adults, and draw a level line for the cabinet top.
  3. Dry-fit and check the plumbing clearance. Slide the cabinet in and confirm the drain stub-out and supply lines land inside the opening. Mark the back panel and cut holes with a hole saw or jigsaw if the vanity has a solid back, leaving about half an inch of clearance around each pipe.
  4. Level and shim the cabinet. Set a level across the top front-to-back and side-to-side. Tap tapered shims under the base and behind the back rail at the studs until it is dead level in both directions. A vanity that is out of level will leave a visible gap under the countertop and let water pool.
  5. Screw the cabinet to the studs. Drive 2.5-inch cabinet screws through the back rail into each stud you marked. Snug, not crushing, so you do not pull the cabinet out of level. Score and snap off the shims flush.
  6. Set the countertop. Run a bead of silicone adhesive along the top edges of the cabinet, lower the top on, and press it down. For a separate backsplash, silicone it to the wall and the top. Wipe the squeeze-out immediately with a damp finger.
  7. Mount the faucet before or after, then connect supplies. It is far easier to install the faucet and drain assembly on the top before the top is fully sealed if access is tight. Attach flexible braided supply lines from the shut-off valves to the faucet tailpieces, hand-tight plus a quarter turn with a wrench.
  8. Assemble the P-trap. Connect the sink tailpiece to the trap and the trap arm to the wall drain, with the slip washers seated and nuts hand-tight plus a nudge. The trap should have a gentle downward slope to the wall.
  9. Turn the water on and check every joint. Open the valves slowly, run the faucet, fill and drain the bowl, and feel every connection with a dry tissue. A slow drip shows up as a damp spot; snug the offending nut a fraction more.
  10. Caulk the perimeter. Run a thin bead of silicone where the countertop and backsplash meet the wall to keep splash water out of the seam.
Wide view of a person's hands fitting a new shower head in a tiled bathroom, in soft early-morning light

Tools and materials

You need a drill/driver, a level, a stud finder, tapered shims, cabinet screws, an adjustable wrench and channel-lock pliers, a hole saw for the pipe cutouts, braided supply lines, a P-trap kit, and a tube of 100% silicone. A new faucet and pop-up drain if you are upgrading. While the plumbing is open it is a natural moment to improve the fixtures the vanity feeds: our shower head roundup and bidet attachment picks cover the upgrades owners most often tackle in the same session, and a quality faucet supply and shut-off matter more than the cabinet finish for a leak-free result.

Golden-hour view of a person's hands fitting a new shower head in a tiled bathroom

Mistakes that cause callbacks

Wide view of a person's hands fitting a new shower head in a tiled bathroom, in warm evening lamplight

When to call a pro

Setting a cabinet and reconnecting to existing shut-off valves is safe DIY. Call a licensed plumber when you need to move the drain or supply lines, add a shut-off valve at the wall, or the existing valves are seized. Plumbing changes past the fixture connections are governed by local code and often require a permit and inspection; codes are jurisdiction-specific, so check with your building department before altering supply or drain lines. If you uncover water damage or mold behind the old vanity, fix the source before you install the new one.

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More from this hub: Bathroom · Installing a vanity light · Replacing a bathroom mirror · Installing a medicine cabinet · Best shower heads · How we rank

Straight Answers

Frequently Asked

Do you tile the bathroom floor before or after installing a vanity?

Tile first, then set the vanity on top of the finished floor. Tiling under the cabinet costs a little more in tile but it is the professional approach: the vanity sits on a flat, sealed surface, the toe kick lines up with the grout, and if you ever swap the vanity for a smaller one you are not left with bare subfloor showing. The only time you tile up to the cabinet instead of under it is a large built-in run where the tile savings are real and you never expect to move it.

How do you install a vanity when the wall is not flat?

Almost no wall is truly flat, so you scribe and shim. Set the cabinet in place, run a level across the back, and slide tapered shims behind it at the stud locations until it is plumb and level in both directions. For a visible side gap against an out-of-square wall, scribe the cabinet side: set a compass to the widest gap, trace the wall profile onto the cabinet, and sand or plane to the line. Then screw through the back rail into studs, not just drywall.

Can you put a vanity over an existing floor drain or rough-in?

Yes, and the rough-in location is what dictates the vanity you can buy. Measure the center of the drain stub-out and the two supply lines from the finished wall and floor before you shop. A standard drain rough-in sits about 16 to 20 inches off the floor and the supplies flank it, but a freestanding vanity with legs needs the plumbing to clear the open bottom, while a full-cabinet vanity hides everything. If the drain lands under a drawer bank, choose a false-front drawer model so the P-trap has room.

What is the standard height for a bathroom vanity?

The old standard was 30 to 32 inches to the countertop, but comfort-height (also called counter-height) vanities at 34 to 36 inches are now the more common choice for adults because they save your back at the sink. If children use the bathroom daily, the lower height or a sturdy step stool is friendlier. Whatever height you pick, confirm the mirror and any wall sconces are set to suit it before the vanity goes in, since those heights key off the finished counter.

Do I need a plumber to install a bathroom vanity?

For a straightforward swap where the drain and supply stub-outs already exist, no. Setting the cabinet, connecting a P-trap, and attaching flexible supply lines to shut-off valves are within reach of a confident DIYer with hand tools. You need a plumber, and often a permit, when you are moving the drain or supply lines, tapping into a new water line, or the existing shut-off valves are corroded and need replacing at the wall. Plumbing past the fixture connections is where local code and licensing come in.