Fix a Leaking Kitchen Faucet

A dripping kitchen faucet is one of those repairs that feels bigger than it actually is. You hear the drip, you think 'plumber bill,' and suddenly it's on the mental pile of things to ignore. But a leaking faucet is actually one of the most accessible fixes in the house—it's mechanical, not mysterious, and the parts are cheap. The leak almost always lives in one of three places: the washers under the handle, the O-rings that seal the cartridge, or the cartridge itself. Once you know which one you're dealing with, the fix is straightforward assembly work. What looks complicated from the outside is just a few stacked components that you can take apart, inspect, and reassemble. A functioning kitchen faucet also matters more than people think. Beyond the waste of water, a leak creates a slow drip that softens wood under the sink, collects in the cabinet, and eventually damages the structure underneath. Fixing it now prevents that.

1. Shut Off the Water First. Locate the shutoff valves under the sink—there should be two, one for hot and one for cold. Turn both clockwise until they stop. If the valves are stuck or missing, shut off the main water supply to the house. Turn on the faucet to release any remaining pressure in the lines.
2. Pop Off the Handle. Look for a small set screw or Allen bolt where the handle meets the body. This is often hidden under a decorative cap that pops off with a flathead screwdriver. Remove the screw, then pull the handle straight up and off. If there's a decorative collar under the handle, unscrew it by hand or with a wrench.
3. Identify Your Faucet Type. Once the handle is off, you'll see either a cartridge (a cylindrical piece that slides straight up) or a stem with a nut underneath. If it's a cartridge, mark its position with a sharpie or take a photo so you reinstall it the same way. For a stem-style faucet, note which way the handle was pointing. Gently pull up on the cartridge or loosen the stem nut with an adjustable wrench to access the washer underneath.
4. Swap the Worn Seals. If you have a stem-style faucet, you'll find a rubber washer and usually an O-ring around the stem. The washer is typically held by a brass screw at the bottom. Remove the screw, take out the old washer (it will be brittle or deformed), and replace it with an identical new washer. Slide the O-ring off the stem and replace it with a new one of the same size. For cartridge faucets, check the O-rings that surround the cartridge—these wear out and cause leaks around the base of the spout.
5. Clear the Valve Seat. The valve seat is the opening where water flows through inside the faucet body. Over time, mineral deposits and debris collect there and prevent a good seal. Use a clean cloth or a soft brass brush to gently clean the inside of the opening. For stubborn deposits, apply a small amount of white vinegar and let it sit for 10 minutes, then scrub. Rinse thoroughly with clean water.
6. Replace the Damaged Seat. If the valve seat is pitted, corroded, or visibly worn, it needs to come out. Faucet seat removal tools come in different sizes depending on your faucet. Insert the tool into the opening, turn counterclockwise, and the seat will unscrew. Take the old seat to the hardware store to match the size. Screw the new seat in by hand first, then tighten with the removal tool, turning clockwise until snug but not forced.
7. Reinstall the Cartridge Right. For a stem faucet, slide the O-ring back onto the stem, then position the new washer under the stem and secure it with the brass screw. For a cartridge faucet, replace any O-rings you removed, then slide the cartridge back into the body in the exact same orientation you noted before disassembly. This alignment is critical—a cartridge installed backwards or rotated will leak. Push down firmly until it seats completely.
8. Reattach the Handle. Slide the decorative collar back onto the body if your faucet has one, then hand-tighten it. Align the handle so it points to the same position it was in before, then slide it onto the stem or cartridge. Insert the set screw or Allen bolt and tighten it firmly—not overtight, just snug. Replace any decorative cap that covers the screw.
9. Restore Water Pressure Gradually. Open one of the shutoff valves under the sink—the cold water valve first. Turn it counterclockwise until water flows. Let water run for 30 seconds to push out any air in the lines. Then slowly open the hot water valve the same way. Turn on the faucet and test both handles through their full range of motion.
10. Verify the Seal Holds. Let the faucet run for a minute, then turn it off. Watch the base where the spout meets the body for any dripping. Check underneath the sink where the supply lines connect to the shutoff valves. If you see drips from the handle area, the cartridge may be rotated incorrectly and needs to come back out. Drips at the base usually mean an O-ring wasn't seated properly or a cartridge needs adjustment.
11. Swap the Cartridge. If you've replaced washers and O-rings and the faucet still drips, the cartridge itself is likely worn and needs replacement. Remove the handle and collar again, then pull out the cartridge. Take it to the hardware store to match the exact model. Install the new cartridge in the same orientation as the old one, reassemble, and test.