Short answer
Remove the P-trap and the old pivot rod, loosen the locknut, and unscrew the flange from the drain body (hold the body so it does not spin). Buy a drain that matches your sink: with overflow slots if the sink has an overflow hole, solid if it does not. Seal the flange with putty or silicone, line up the overflow opening in the body with the sink’s overflow channel, tighten the gasket and locknut, then reconnect the tailpiece, pivot rod and trap. Test by filling the sink to the overflow.
Pick the right replacement first
Three things decide which drain you buy:
- Overflow or not. Look for a hole near the rim of the sink. If it is there, buy a drain body with overflow slots. If not, buy a solid body. VIGO explains why: a slotted body in a sink with no overflow lets water out through the slots when the stopper is closed.
- Stopper style. If your faucet has a lift rod behind the spout, a lift rod pop-up uses it. A push button drain needs no linkage at all. Hunker and Signature Hardware both lay out the styles.
- Size. The tailpiece is 1-1/4 inch on nearly all bathroom sinks (HomeGuide). The hole in the sink is not standard, so measure it and buy to the range on the box.
The bathroom sink drain buying guide compares the styles, and the drain picker narrows it down in four taps.
What you need
- Replacement pop-up drain with overflow, to match a sink with an overflow holeFind it
- Pop-up drain without overflow for sinks with no overflow holeFind it
- Plumber’s putty or 100% silicone whichever the drain maker specifiesFind it
- Slip-joint pliers two pairs help: one to hold, one to turn
- Basin wrench handy in a tight cabinetFind it
- Plastic putty knife for old putty
- Bucket and ragsFind it
- 1-1/4 in slip washers if the trap washers are wornFind it
How to replace a bathroom sink drain, step by step
Remove the P-trap
Clear the cabinet and put a bucket under the drain. Loosen both slip nuts on the P-trap and take it off. Empty it into the bucket.
Disconnect the pivot rod
Squeeze the spring clip to free the pivot rod from the clevis strap, then unscrew the pivot nut on the back of the drain body and pull the rod out. Lift out the old stopper.
Loosen the locknut
Turn the large locknut under the sink counterclockwise, by hand if you can or with slip-joint pliers or a basin wrench. Spin it down the drain body along with the washer and gasket.
Unscrew the flange from the body
The flange on top threads into the drain body below. Have a helper hold the body from below with pliers so it does not spin, and unscrew the flange from above. Then push the body down and out. Corroded bodies sometimes need penetrating oil and patience.
Clean the drain hole
Scrape the old putty or silicone off the sink with a plastic putty knife and wipe it dry, top and bottom. Clear any slime from the overflow opening inside the hole while you can reach it.
Seal under the flange
Press a rope of plumber’s putty, about pencil thick, around the underside of the replacement flange, or run a bead of silicone, whichever the drain maker calls for. Use stain-free putty or silicone on stone or marble.
Insert the body and line up the overflow
From below, push the drain body up into the hole with the gasket and locknut threaded on loosely, and thread the flange into it from above. Before tightening, turn the body so the overflow opening on its side faces the sink’s overflow channel, and the pivot rod port faces the back wall.
Tighten the gasket and locknut
Hold the flange from above and tighten the locknut from below until the gasket is snug and the body cannot turn. Check the alignment again. Do not overtighten, especially on a plastic body.
Fit the tailpiece and reconnect the trap
Thread the tailpiece onto the bottom of the drain body if it is separate, then refit the P-trap with good slip washers. Hand tight plus a little more on plastic nuts.
Reinstall the pivot rod and adjust
Drop the stopper in, slide the pivot rod into the port so it engages the stopper, and tighten the pivot nut. Clip the rod into the clevis strap and set the strap on the lift rod so the stopper seals when the rod is up and opens fully when it is down. Skip this for a push button drain.
Leak test, including the overflow
Wipe the putty squeeze-out. Close the stopper and fill the sink until water runs into the overflow, and let it run there for a minute. Then open the stopper and drain the full bowl. Check the flange, locknut, pivot nut and every slip nut with a dry paper towel.
Why the overflow test matters
Water from the overflow hole runs down a channel inside the sink and enters the drain body through the overflow slots, which sit inside the sink’s drain hole between the flange seal on top and the gasket underneath. If those slots are not lined up with the channel, or the gasket does not seal around them, overflow water leaks down the outside of the drain body. You will not see it when you just run the tap. Filling the sink to the overflow is the only way to check.
Common problems after the swap
Drip at the pivot nut. Snug the pivot nut a little. If it still drips, the ball seal inside may be seated wrong or worn.
Stopper does not open far enough. Move the pivot rod to another hole on the clevis strap. How to remove a sink stopper explains the adjustment.
Water rises from the slots with the stopper closed. The drain has overflow slots but the sink has no overflow. Swap it for a drain without overflow.
Leak at the trap. A slip washer is missing, flat or backwards. Bathroom traps are 1-1/4 inch; see the P-trap guide for parts.
Vessel sinks and grid drains
Vessel sinks usually have no overflow and need a longer drain body that spans the bowl and the counter. See the vessel sink drain guide. If you want no stopper at all, a grid drain installs the same way as above, without the pivot rod; match its overflow type to the sink too.
Replacing the kitchen drain too? See how to replace a kitchen sink drain.
Questions people ask
How do I remove an old bathroom sink drain?
Take off the P-trap and the pivot rod, then loosen the large locknut under the sink. Unscrew the flange from above while someone holds the drain body from below, often with pliers, so it does not just spin. Push the body down and out and scrape off the old putty.
Do I need a pop-up drain with or without overflow?
Match the sink. If the sink has an overflow hole near the rim, you need a drain body with overflow slots. If it has no overflow hole, use a drain without overflow, or water can rise out of the slots when the stopper is closed.
Should I use plumber’s putty or silicone on a bathroom sink drain?
Either can work under the flange. Some drain makers specify one or the other, and stone, marble and some composite sinks can stain from oil-based putty, so use stain-free putty or silicone there. Follow the instructions in the box.
Why does my bathroom sink drain leak at the overflow?
Usually the overflow opening in the drain body is not lined up with the sink’s overflow channel, or the gasket is not sealing around it. Water from the overflow then runs down the outside of the drain body. Loosen the locknut, line it up, and retighten.
Can I replace a lift rod pop-up with a push button drain?
Yes. A push button drain needs no linkage, so you leave the lift rod and pivot rod out. The hole behind the faucet stays open unless the faucet came with a cap for it.
Sources
Last reviewed October 12, 2026. Parts, sizes and listings change; check the product details before you buy, and follow the maker’s instructions.