Fix a Leaking Kitchen Faucet

A dripping kitchen faucet is one of those problems that feels small until you realize it's costing you money and sleep. That steady plink in the sink isn't just annoying; it's also wasting water and hinting that internal seals are breaking down. The good news is that fixing one is straightforward work that doesn't require a plumber. Most leaks originate in one of three places: the rubber washer at the base of the spout, the cartridge that controls water flow, or the O-rings that seal the handle. Identify where your water is coming from—dripping from the spout itself, pooling under the handles, or leaking from the base—and you'll know exactly what to replace. This guide walks you through diagnosing the leak and making the repair with basic hand tools.

1. Shut Off the Water First. Locate the shut-off valves under your sink. They're usually oval knobs on the hot and cold supply lines. Turn both clockwise until they stop. If you don't have shut-off valves under the sink, turn off the main water supply to the house. Open the faucet to release any remaining pressure in the lines.
2. Know What You're Facing. Look at your faucet closely. Is it a single-handle model (one lever or knob), a two-handle model (separate hot and cold), or a pull-down or pull-out spray faucet? Single-handle faucets typically use a cartridge inside the handle. Two-handle models usually have washers under each handle. Write down what you see—it determines which seal you'll be replacing.
3. Expose the Set Screw. Most kitchen faucets have a decorative cap covering the base of the handle. Gently pry it off with a flat screwdriver or your fingernail. Underneath, you'll find a set screw (usually a hex bolt). Loosen it counterclockwise with an appropriately sized hex wrench or screwdriver. Don't remove it completely—just loosen enough that you can pull the handle free.
4. Remove Handle and Collar. Once the set screw is loose, pull the handle straight up and away from the faucet body. It should come free without forcing. If it's stuck, apply penetrating oil and wait five minutes. Below the handle, you'll see a decorative collar nut (also called an escutcheon). Use an adjustable wrench to turn it counterclockwise and remove it. Some faucets have a second collar under the first—remove that too if present.
5. Extract the Broken Seal. For single-handle cartridge faucets: the cartridge sits directly under where the handle was. It's a cylindrical piece, usually plastic or metal, with a notch at the top. Use a cartridge puller (a specialized tool available at hardware stores for $10–15) to grip and pull it straight up. The tool prevents damage better than pliers. For two-handle washers: look under the handle for a small hex nut called the packing nut. Use a wrench to loosen it counterclockwise. Once loose, you'll see the brass stem underneath—remove it by turning counterclockwise.
6. Swap the Seal. For two-handle faucets with washers: at the bottom of the brass stem, you'll find a small rubber washer held in place by a brass screw. Remove the screw, pull out the old washer, and replace it with an identical new one. The washer is usually 1/2 inch or 5/8 inch—bring the old one to the store for comparison. For cartridge faucets: you're replacing the entire cartridge, so skip this step and move to reinstallation. For O-ring leaks (water pooling at the base of the spout), locate the O-rings on the spout's underside, cut them off with a utility knife, and slide new rings of the same size onto the spout.
7. Check for Hidden Damage. Before reassembling, inspect the valve seat—the small depression where the washer or cartridge sat. Use a flashlight and look inside. If you see mineral buildup, corrosion, or pitting, the seat needs cleaning or replacement. For light buildup, wrap fine steel wool around your finger and gently scrub the seat. For serious pitting or damage, the seat needs replacement with a specialized valve-seat tool (an advanced step; consider a plumber for this). If it's clean, move ahead with reassembly.
8. Install the New Seal. For washers: slide the stem back into the faucet body, aligning the notches. Turn it clockwise by hand until it seats, then hand-tighten the packing nut on top. Don't over-tighten—you want it snug, not forced. For cartridges: slide the new cartridge into place, making sure the notch at the top aligns with the notch in the faucet body. Push it down firmly until it seats. Install the collar nut and tighten with a wrench until snug.
9. Put It Back Together. Replace the decorative collar nut and hand-tighten it. Slide the handle back onto the stem or cartridge, aligning it with the notch. Insert the set screw and tighten it firmly but not aggressively—over-tightening strips the threads. If there's a handle cap, snap it back into place. Wipe any water or debris from the faucet base.
10. Restore Water Carefully. Slowly turn the shut-off valves under the sink counterclockwise. Listen for air hissing out of the faucet—this is normal. Once water flows smoothly and steadily, run it for 30 seconds to flush out any debris loosened during disassembly. Check under the sink for any new leaks around the valve connections.
11. Verify the Fix Works. Turn the faucet handle on and off several times. The water should flow smoothly and shut off crisply without dripping. Check the spout for drips while the handle is in the off position—wait at least one minute. Also inspect under the sink and at the base of the faucet for pooling or seeping. Leave the cabinet open under the sink for 24 hours and check periodically. If water appears, you may have missed a seal or the valve seat has damage requiring professional service.