How Do You Replace a Leaking Bathroom Sink Pop-Up Drain?

To replace a leaking bathroom sink pop-up drain, place a bucket under the plumbing, loosen the P-trap slip nuts, and slide the trap off the drain tailpiece. Unscrew the large mounting nut underneath the basin with pliers, push the old drain out, and clean the sink hole. Apply plumber's putty or silicone to the new drain flange, drop it in, and tighten the lower gasket and nut assembly from below until snug. Reconnect the horizontal pivot rod and the P-trap, then run water to test for leaks. Doing this job yourself takes about an hour, requires only a few basic hand tools, and saves a typical $150 to $250 plumbing service call.

• Check your sink for an overflow hole before buying a replacement drain, as the parts are not interchangeable.
• Discard the foam top gasket included in most kits and use plumber's putty or 100% silicone for a reliable seal.
• Hand-tighten the mounting nut beneath the sink, then add only a half-turn with pliers to avoid cracking the nut or distorting the rubber seal.
• Test the final installation by filling the sink completely and draining it at once to simulate maximum water pressure on the joints.

What Tools and Materials Do You Need to Replace a Pop-Up Drain?

Before you start taking apart the plumbing, you need to purchase the correct replacement drain assembly. Look inside your sink basin near the rim. If there is a small hole designed to prevent the sink from overflowing, you must buy a drain assembly 'with overflow.' If the basin is smooth with no hole, which is common on modern vessel sinks, you must buy a drain 'without overflow.' Installing the wrong type will either cause a massive leak or prevent your sink from draining properly. A quality replacement drain will cost between $15 and $40 in 2026, depending on the finish and material.

You will only need a few basic tools to complete the replacement. A standard 10-inch (254 mm) pair of slip-joint pliers (often called Channellocks) is essential for loosening the large locknut beneath the sink and dealing with stubborn P-trap connections. You will also need a small bucket to catch standing water, some old rags for cleanup, and either a small tub of plumber's putty or a tube of 100% silicone sealant for the top flange.

• Replacement pop-up drain assembly (matching your overflow type)
• 10-inch (254 mm) slip-joint pliers
• Plumber's putty or 100% silicone sealant
• Small bucket and cleaning rags

How Do You Safely Remove the Old Rusted or Stuck Pop-Up Drain?

Start by clearing everything out of the vanity cabinet and placing a bucket directly under the P-trap. The P-trap is the U-shaped pipe that holds water to block sewer gases. Find the two slip nuts securing the trap to the wall pipe and the vertical drain tailpiece. Loosen both nuts by turning them counterclockwise. If they are plastic, you can usually loosen them by hand. If they are metal and stuck, carefully use your pliers. Slide the nuts back and pull the P-trap straight down, emptying the trapped water into your bucket.

Next, disconnect the horizontal pivot rod that controls the stopper. Unscrew the small retaining nut on the back of the drain tailpiece and pull the rod straight back. You can now lift the old stopper out of the sink basin. Finally, use your pliers to grab the large mounting locknut pressed against the underside of the sink. Turn it counterclockwise to loosen it. If a metal nut is completely seized by rust and mineral deposits, spray it with penetrating oil and wait 15 minutes. Once the nut is off, push the entire drain assembly straight up and lift it out of the basin.

Why Should You Throw Away the Factory Foam Top Gasket?

When you open a new pop-up drain kit, you will usually find a thin, white foam ring designed to sit between the metal drain flange and the top of the sink basin. A common judgment call a professional plumber makes differently from a beginner is throwing this foam ring straight into the trash. Beginners use it because the instructions show it in the diagram, but it is notoriously unreliable.

The factory foam gasket rarely compresses evenly. It often leaves the metal flange sitting slightly too high, causing a small ring of water to pool around the drain instead of flowing down. Over time, harsh chemical drain cleaners also eat away at the foam, leading to leaks. Instead of the foam, roll a 0.5-inch (13 mm) thick rope of plumber's putty and press it around the underside of the new metal flange before dropping it into the sink. As you tighten the drain from below, the putty will squeeze out, creating a permanent, flush, watertight seal. Note: If you have a porous stone, composite, or acrylic sink, plumber's putty can leave a yellow stain, so use a bead of 100% silicone instead.

How Do You Install the New Drain Flange and Tailpiece?

Thoroughly clean the sink opening with a rag and an all-purpose cleaner. Any old putty, hard water scale, or soap scum left behind will prevent the new drain from sealing. Once the hole is spotless and dry, apply your plumber's putty or silicone to the underside of the top flange. Push the new drain body down through the sink hole. Ensure that the opening on the side of the tailpiece (where the pivot rod will eventually go) is facing straight back toward the wall.

Working from underneath the sink, slide the thick, tapered rubber washer (often called a mack washer) onto the tailpiece. The tapered, sloped side must face up into the sink opening. Next, slide on the thin friction ring, which is usually made of hard plastic or stiff cardboard. This ring is crucial because it allows the metal or plastic locknut to spin without grabbing and twisting the rubber washer out of place. Thread the locknut onto the tailpiece and tighten it as far as you can by hand. Use your pliers to tighten it exactly one-half turn further. Wipe away the excess putty that squeezes out in the sink basin.

How Do You Connect the Pop-Up Stopper Rod and Pivot Nut?

With the main drain body secure, drop the new stopper into the top of the sink. Look closely at the bottom of the stopper; it has a plastic loop with a hole in it. Rotate the stopper so this loop faces the back of the sink. Crawl under the sink and insert the horizontal pivot rod through the hole in the side of the tailpiece. You should feel the rod pass through the loop on the bottom of the stopper. Hand-tighten the pivot nut to hold the ball joint in place, but do not overtighten it, or the stopper will be too stiff to operate.

Attach the lift rod assembly that comes down from the faucet to the horizontal pivot rod using the metal clevis strap and the V-shaped spring clip. Pinch the spring clip to slide it onto the pivot rod, insert the rod through one of the holes in the clevis strap, and release the clip to lock it. Pull the lift rod up and down from above the sink to ensure the stopper opens and closes completely. If it does not open far enough, move the pivot rod to a lower hole on the clevis strap.

How Do You Reconnect the P-Trap and Test for Leaks?

Slide the P-trap back onto the wall pipe and the new drain tailpiece. Ensure the tapered nylon washers inside the slip joints are facing the correct direction; the sloped edge must point toward the threaded joint it is sliding into. Hand-tighten the slip nuts firmly. Avoid using pliers on plastic slip nuts unless absolutely necessary, as it is very easy to cross-thread or crack the plastic.

To test your work, do not just run the faucet on a low stream. Close the pop-up stopper and fill the sink basin completely to the rim. Once full, pull the stopper open to release the water all at once. This sudden rush of water puts maximum pressure on the drain seals and the P-trap joints. Shine a flashlight under the sink and wipe every joint with a dry piece of toilet paper. If the paper stays dry, you have successfully completed the installation.

What Is the Most Common Reason a New Pop-Up Drain Still Leaks?

The most frequent failure mode for a newly installed pop-up drain is overtightening the main mounting locknut beneath the sink. When a beginner spots a drip coming from the rubber mack washer, their first instinct is to grab a wrench and crank the nut down as hard as possible. This is a costly mistake.

Overtightening causes two major problems. First, if you are using a plastic drain assembly, the locknut will simply crack down the middle, ruining the part and requiring a full replacement. Second, excessive pressure will squeeze the rubber cone washer so hard that it deforms, bulging out of the sink opening and creating tiny channels for water to escape. To avoid this, always stop tightening when the nut is firmly snug against the friction ring. If a leak persists, loosen the nut entirely, ensure the rubber washer is seated straight, and tighten it again carefully.

Frequently asked questions