Renovation guides

How to install a bathroom vanity and sink yourself: step by step

Goes in after the floor tile so the vanity sits on the finished floor. Level it, anchor it into studs, connect like-for-like to the existing shutoffs, and watch it for a day.

Difficulty 2 of 5 · about half a day · you can do this

Photo of your room, the look you pick, then this guide with the materials counted for your room.

Step by step

1. Step 1 of 13

   Shut the water off and prove it

   Close both shutoff valves under the sink and open the faucet — the flow should stop completely and then die to nothing. If a valve will not close all the way, stop here: that is a plumber's job, and forcing an old valve usually breaks it.

2. Step 2 of 13

   Disconnect and remove the old vanity

   Bucket under the trap, loosen the supply nuts, then the trap slip nuts, and let the water drain out. Cut the caulk line at the wall with a knife, back out the cabinet screws, and walk the old cabinet out.

3. Step 3 of 13

   Inspect what was hiding behind it

   Look for water stains, soft drywall, rot in the subfloor, or mold at the base of the wall. Smell it. Anything soft or dark stops the install until it is repaired — a new vanity over rot buys you nothing.

4. Step 4 of 13

   Mark the studs and the rough-in heights

   Find the studs and pencil them above the vanity line. Measure the height and offset of the drain stub and both valves from the floor and transfer those to the back of the new cabinet.

   Ready to set the vanity?

   • Both shutoff valves close fully — no drip at the faucet, no weep at the stem
   • Floor tile is finished and cured; the vanity will sit on the finished floor
   • Wall and subfloor behind the old vanity are dry and sound
   • Studs marked, drain and supply heights transferred to the new cabinet
   • New supply lines and a new trap kit on hand — nothing reused
   • Bucket, towels, and a headlamp in place

5. Step 5 of 13

   Cut the cabinet back for the plumbing

   Drill or cut openings a little oversize so the cabinet can slide home without fighting the pipes. Dry-fit, pull it back, adjust — do not force it.

6. Step 6 of 13

   Set it in place and shim it level

   Slide the cabinet against the wall and put the level across the top front to back and side to side. Shim under the base until both directions read level, with the shims under the cabinet's bearing points, not just the front edge.

7. Step 7 of 13

   Anchor into the studs

   Drive cabinet screws through the rear rail into the studs you marked, snug but not crushing the rail out of level. Recheck level after fastening, then trim the shims flush.

8. Step 8 of 13

   Fit the faucet and drain to the top before it goes on

   Every faucet is easier to install off the cabinet. Mount the faucet and the pop-up drain body on the top while you can still reach the nuts — a ring of plumber's putty under the drain flange, gasket per the instructions underneath. Then set the top on the cabinet and secure it per the maker's instructions.

9. Step 9 of 13

   Connect supplies: hand-tight plus a quarter turn

   New braided lines, hot to the left. Thread the nuts on by hand until they seat, then bring them up with a wrench about a quarter turn more. No thread tape on compression fittings. Do not over-crank — that is what causes the leak you are trying to prevent.

10. Step 10 of 13

    Assemble the P-trap

    Dry-fit the tailpiece, trap, and wall arm so the trap hangs plumb and the arm slopes slightly down toward the wall. Slip washers go in the right direction per the kit drawing; slip nuts are hand-tight plus a light nudge only — plastic nuts crack easily.

11. Step 11 of 13

    Open the valves slowly and look

    Open each shutoff a quarter turn at a time with a hand and a paper towel at each joint. Run hot and cold, fill the bowl and let it drain fast, and watch the trap joints while the water is moving — that is when a bad slip nut shows itself.

12. Step 12 of 13

    Dry everything and watch it for 24 hours

    Wipe every joint bone dry, lay a dry paper towel under the trap and under each valve, and check at an hour and again the next day. A spot the size of a dime means a joint needs a small turn, not a full re-do.

13. Step 13 of 13

    Caulk and hang the doors straight

    A thin bead of silicone where the backsplash meets the wall and where the cabinet base meets the tile. Adjust the door hinges so the gaps are even and nothing swings open on its own.

    Quality check

    • 24 hours dry: no water on the towels under the valves or the trap
    • Cabinet level in both directions and anchored into studs
    • Trap hangs plumb, arm slopes toward the wall, no standing water in the bowl
    • Faucet runs hot on the left, pop-up opens and closes, sink holds water
    • Silicone at the backsplash and the cabinet base, tooled once
    • Doors and drawers even, nothing rubbing or swinging open

Draft guide written from standard practice, not yet reviewed by a licensed pro. Follow product labels where they differ.

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