Fix a Leaking Bathroom Sink Faucet

Dripping faucets are one of those small annoyances that compounds. That steady drip isn't just irritating—it's waste. A single leaking faucet can cost you hundreds of gallons a year and show up on your water bill. The good news is that fixing one is straightforward work that doesn't require a plumber. The leak is almost always happening inside the valve body, where rubber washers and seals wear out over time. Once you know what type of faucet you have, you'll identify exactly which part failed and swap it out. Most homeowners can do this in under an hour with basic tools and a $10 repair kit from the hardware store.

1. Shut Down the Supply First. Locate the shutoff valves under the sink—there should be one for hot and one for cold. Turn both counterclockwise until they stop. Then open the faucet to release any remaining pressure in the lines. If there are no shutoff valves under the sink, you'll need to turn off the main water supply to the house.
2. Extract the Handle Screw. Look for a small screw, usually hidden under a decorative cap or in a slot on the handle itself. Pop off the cap with a flathead screwdriver if needed, then unscrew the handle screw. Pull the handle straight up and away from the faucet body. Some single-lever faucets have the screw under a small plastic plug—pry it out gently with your screwdriver.
3. Loosen the Packing Nut. Once the handle is off, you'll see a large nut or collar at the base of the stem. This is the packing nut. Use an adjustable wrench to turn it counterclockwise. It should come off easily. If it's stuck, apply a bit of penetrating oil and wait a few minutes before trying again.
4. Find the Culprit Inside. With the packing nut off, you can now pull the entire stem straight up and out of the faucet body. It may take a little wiggling. Once it's out, lay it on a clean towel and examine it. This stem is the heart of your faucet, and the leak is happening because something inside it has worn out.
5. Swap Out the Washer. At the bottom of the stem, you'll find a small brass screw holding a rubber washer in place. This washer is usually the culprit. Unscrew it with a screwdriver, remove the old washer, and note its size. Take it to the hardware store if you're unsure, or buy an assorted washer kit that covers most common sizes. Screw the new washer in place with the brass screw—snug it down but don't overtighten.
6. Lubricate & Install Fresh Seal. Just above the washer, you'll see a small rubber ring (the O-ring) around the stem. This can also leak and fail independently of the washer. If it looks dried out, cracked, or hardened, remove it and slide a new one on. O-rings come in various sizes—bring the old one to the store to match it, or buy a kit with several sizes. Coat the new O-ring lightly with plumber's grease before sliding it on. This makes it slip on easier and helps it seal better.
7. Reinsert Stem Smoothly. Once your new washer and O-ring are in place, you're ready to slide the stem back into the faucet body. Line it up so it goes in straight and seats fully in the body. You should feel it settle into place. It's not a tight fit—it should slide in smoothly. If it's fighting you, pull it out and check that the O-ring isn't twisted.
8. Secure the Packing Nut. Slide the packing nut back onto the stem and hand-tighten it first. Once it's seated, use the adjustable wrench to tighten it clockwise—firm, but not aggressive. You want it tight enough to stop any leaking around the stem, but not so tight that the handle becomes hard to turn.
9. Reattach the Handle. Slide the handle back onto the stem with the spout pointing in the direction you want it. Align the handle screw hole, insert the screw, and tighten it by hand first, then with a screwdriver. Don't strip it—just snug. If the handle has a decorative cap, snap it back in place.
10. Restore & Inspect. Turn the shutoff valves under the sink back on—both hot and cold. Open the faucet and let the water run for a few seconds to clear any air in the lines. Now watch the base of the faucet and the connection points. There should be no dripping from the spout when you turn it off, and no leaking around the packing nut or handle base.
11. Fine-Tune the Seal. If you see water leaking from around the stem (where the handle connects), the packing nut needs to be tighter. Don't panic—this is common. Use the adjustable wrench to tighten it another quarter turn, then test again. Keep doing this in small increments until the leak stops. You want the tightest setting that still allows the handle to move smoothly.
12. Monitor for 24 Hours. A slow drip from the spout can take a few hours to show up as the new parts settle and seal properly. Check the faucet before you go to bed and again in the morning. If it's still dripping, you may need to replace the seat or cartridge instead of just the washer—see the troubleshooting section for how to determine this.