How to Install a New Bathroom Vanity

Replacing a bathroom vanity is one of those projects that looks intimidating but breaks down into straightforward steps—remove old, install new, reconnect water. The vanity is the anchor of bathroom function and style, so getting it right matters both for how your bathroom works and how it feels. A solid installation means no leaks, no wobble, and a cabinet that'll handle daily use for years. The trick is taking your time with the connections and not forcing anything into place.

1. Shut Off the Water Supply. Locate the shut-off valves under the sink and turn them clockwise until they stop. Turn on the faucet to release pressure and empty the lines. Place a bucket under the connections to catch residual water.
2. Detach All Water Lines. Use an adjustable wrench to loosen the supply line nuts at the shut-off valves first, then at the faucet connections. Unscrew the P-trap or S-trap under the sink where the drain exits. Have your bucket ready; some water will spill.
3. Pull Out the Old Cabinet. Check for caulk or adhesive around the top edges and score it with a utility knife to break the seal. Unbolt the cabinet from the wall studs using a drill or wrench, working from the inside if possible. Slide the cabinet straight out and away from the wall—enlist a helper; most vanities are awkward and heavy.
4. Find and Mark the Studs. Look at the wall studs where the old vanity bolted on. If they're solid, they're your anchor points. If there's damage or rot, mark those areas and plan to reinforce with blocking. Wipe away old caulk, adhesive, and debris. Mark your stud locations with pencil at the height where your new vanity will sit.
5. Get It Level and Secure. Move the new cabinet into place and slide it tight to the wall. Set a level on top and check front-to-back and side-to-side. Use shims under the base to adjust until it's perfectly level—don't rely on the wall to be plumb. This matters more than you think; crooked vanities make drawers stick and water pools on the countertop.
6. Anchor to the Wall. Once level, mark the bolt holes through the vanity back into the studs. Drill pilot holes into the studs if needed, then thread lag bolts or cabinet screws through the vanity back and into the studs. Tighten firmly but don't overtighten; you want snug, not crushing the cabinet.
7. Reconnect All Supply Lines. Thread supply lines back onto the shut-off valves and faucet inlets by hand, then tighten with a wrench. Don't over-crank; snug is enough. Reconnect the P-trap or drain line, hand-tightening first, then tightening with a wrench. Leave it finger-tight plus a quarter turn.
8. Check for Leaks and Seal. Turn the shut-off valves back on slowly and turn on the faucet to check for leaks at all connection points. Let water run for a minute. Check under the sink with a flashlight. Once you're sure there are no leaks, apply silicone caulk around the seams where the vanity meets the wall and countertop. Let it cure per the caulk manufacturer's instructions before using the sink.