Install a Pop-Up Drain Assembly in Your Bathroom Sink

Pop-up drains fail in predictable ways. The stopper stops sealing, the pivot rod corrodes through, or the entire assembly develops that persistent drip beneath the sink that announces itself with a rust stain on the cabinet floor. Replacing the whole unit costs less than fifteen dollars and solves all three problems at once. A proper installation means a watertight seal at every connection, a stopper that moves smoothly through its full range, and a pivot rod positioned so it won't work itself loose over the next decade. This is fundamental bathroom plumbing—the kind of repair that separates homeowners who call for help from homeowners who reach under the sink with a wrench. The work happens in two zones: above the sink where the flange seats into the drain hole, and below where the mechanical linkage connects. Most failures trace to poor sealing at the flange or improper pivot rod tension. Get both right and you've installed something that will outlast the faucet above it. The job requires working in the cramped space beneath a sink, so clear out everything under there first and get a headlamp if your under-sink lighting consists of whatever leaks past the cabinet door.

1. Remove the Old Drain Assembly. Place a bucket under the P-trap and loosen the slip nuts connecting the tailpiece to the trap. Unscrew the pivot rod nut on the drain body and pull out the pivot rod—the stopper will come free from above. From beneath, unscrew the large locknut holding the drain body to the sink using a basin wrench or channel locks. Lift the old drain body down through the sink opening and scrape away all old putty or gasket material from around the sink's drain hole until you're down to clean porcelain or metal.
2. Prepare the New Drain Flange. Roll plumber's putty into a rope about half an inch thick and press it around the underside of the drain flange in a complete circle. If your drain came with a rubber gasket instead, skip the putty and set the gasket in place—never use both. The putty creates the watertight seal between the flange and the sink surface, so apply it generously enough that some will squeeze out when you tighten things down.
3. Install the Flange and Lock It Down. Drop the flange into the sink drain hole from above, pressing down firmly so the putty makes contact all the way around. From beneath the sink, slide the rubber gasket and then the cardboard friction washer onto the drain body threads, then thread on the large metal locknut hand-tight. Hold the flange steady from above with one hand while you tighten the locknut from below with your basin wrench—tighten until you see a thin, even bead of putty squeeze out around the flange, then give it another quarter turn.
4. Attach the Tailpiece. Wrap three layers of Teflon tape clockwise around the threads at the bottom of the drain body. Thread the tailpiece onto the drain body and tighten it firmly by hand—this connection doesn't need a wrench. The tailpiece length matters: it should extend down far enough to connect to your P-trap with the slip nut, typically leaving about an inch of overlap into the trap inlet.
5. Insert the Stopper and Pivot Rod. Drop the stopper into the drain from above, orienting it so the hole in the bottom of the stopper shaft faces toward the back of the sink. From below, slide the pivot rod through the opening in the tailpiece, threading it through the hole in the stopper shaft, then thread the pivot rod nut onto the tailpiece finger-tight. Test the stopper by pulling the pivot rod—the stopper should rise and fall smoothly.
6. Connect the Lift Rod Assembly. Insert the lift rod down through the hole in the back of the faucet deck and attach the clevis strap to its bottom end with the provided clip. Adjust the pivot rod's position in the clevis strap, using one of the several holes provided, until pulling up on the lift rod knob fully opens the stopper and pushing it down fully closes it. Tighten the clevis screw to lock everything in place, then snug up the pivot rod nut.
7. Reconnect the P-Trap. Align the tailpiece with the P-trap inlet and slide the slip nut and washer into position. Thread the slip nut onto the trap hand-tight, then snug it with channel locks—just tight enough to compress the washer and create a seal, not wrench-tight. Wipe all connections clean so you can spot any leaks clearly.
8. Test for Leaks and Adjust. Fill the sink to the overflow, then open the stopper and let it drain while you watch every connection from below with your headlamp. Check the flange seal, the tailpiece threads, the pivot rod nut, and all slip nuts on the P-trap. Cycle the stopper up and down several times to verify smooth operation. Wipe away the excess putty from around the flange with a plastic putty knife, leaving a clean edge.