How do I stop a leaky faucet?

Short answer

Stop a leaky faucet by turning off the water supply, disassembling the faucet, and replacing the worn parts—typically a washer and valve seat (compression faucets) or a cartridge/ceramic disc and O-rings (cartridge or disc faucets). Reassemble, turn water back on, and test. Most fixes take 30–90 minutes and cost $5–$40 in parts.

Why faucets leak and how to identify yours

A steady drip after the faucet is closed usually means a worn seal inside the valve. The fix depends on faucet type:
- Two handles that turn several rotations: compression faucet (uses rubber washers and seats).
- Two handles with only a quarter turn: ceramic disc faucet.
- Single handle, smooth travel: cartridge or ceramic disc.
- Older single handle, slightly notchy feel and dome cap: ball-type.

Leaking at the spout is usually a valve issue. Leaking around the base of the spout is often an O-ring. A weak or erratic stream can be an aerator clogged with mineral deposits.

Tools and materials

Adjustable wrench (6–10 inch)
Phillips and flathead screwdrivers
Allen/hex keys for handle set screws
Slip-joint pliers with soft jaws or a rag to protect finishes
Replacement parts: washers, O-rings, cartridges, or seats (brand-specific helps)
Plumber’s silicone grease (not petroleum)
Plumber’s tape (PTFE) for threads (if applicable)
Seat wrench or hex seat tool (for compression seats)
White vinegar and a small brush for mineral deposits
Towels/rags and a small bucket
Flashlight

Common set screw sizes for handles:
Imperial: 3/32", 7/64", 1/8" Metric: 2 mm, 2.5 mm, 3 mm

Step-by-step (all faucet types)

Turn off water: Close the hot and cold shutoff valves under the sink by turning clockwise. If stuck, do not force—see When to call a pro. Open the faucet to relieve pressure.
Plug the drain: Use a sink stopper or a rag to avoid losing small parts.
Remove handle: Pry off the decorative cap if present, loosen the screw or set screw, and lift off the handle.
Disassemble the valve:
- For single-handle: remove the dome cap and retaining nut to access the cartridge or ball/disc assembly.
- For two-handle: remove the trim and unscrew the stem assembly.
Inspect and clean: Look for torn O-rings, cracked cartridges, worn washers, or pitted seats. Soak mineral buildup in vinegar and scrub gently.
Replace worn parts: Use OEM parts when possible (brand and model matter). Lubricate O-rings and moving parts with silicone grease.
Reassemble and align: Refit components in the same order. Hand-start threads to avoid cross-threading. Reinstall handle.
Turn water on slowly: Check for leaks while operating the faucet through full travel. If it drips for 1–2 minutes then stops, that’s normal residual water; persistent drip means recheck seals.

Time: 30–90 minutes for most DIYers. Costs: washers and O-rings $2–$10, valve seats $3–$8 each, cartridges/disc assemblies $10–$50+ depending on brand.

Fixes by faucet type

Compression (two handles, multiple turns)

Replace the rubber washer at the end of the stem and the stem packing/O-ring.
Inspect the valve seat inside the body. If it’s rough or pitted, use a seat wrench to remove and replace; if fixed (non-removable), use a seat dresser to resurface lightly.
Reassemble, snug the packing nut just enough to stop seepage—do not overtighten.

Cartridge or ceramic disc (single or dual handle, quarter turn)

Pull the cartridge straight up after removing the retaining clip/nut. Match the new cartridge by brand and part number (Moen 1225/1222, Delta, Kohler, Grohe, etc.).
Replace any O-rings on the cartridge body and lubricate lightly. Ensure orientation tabs line up during installation.

Ball-type (older single handle)

Replace the rubber seats and springs under the ball. Kits are inexpensive and include all wear parts. Pay attention to spring orientation (narrow end up against the seat).

Base-of-spout leaks (pull-out/pull-down sprayers or goosenecks)

Remove spout and replace the large spout O-rings. Clean the spout shank and valve body, grease O-rings, and reassemble.

Weak stream or spray irregularities

Unscrew the aerator at the spout tip, soak in vinegar for 30 minutes, rinse, and reinstall. Replace if corroded or damaged.

Safety and care

Turn off power to a garbage disposal if you’ll be reaching near it while working under the sink. Unplug or flip the breaker.
Protect finishes with tape or a cloth under plier jaws. Use the correct size tools to prevent slips.
Avoid petroleum-based lubricants—they degrade rubber.
Watch for hot water in lines; relieve pressure before disassembling.

Tips for best results

Bring the old part to the store or check the manufacturer’s parts diagram to ensure a match.
Take photos during disassembly so reassembly order is clear.
If shutoff valves seep or don’t fully close, cycle them back and forth gently; if they still leak, use the main house shutoff and plan to replace the angle stops soon.
Keep spare O-rings and washers in a small organizer; they’re inexpensive and save time.

Common mistakes to avoid

Overtightening the packing nut, which makes the handle stiff and can damage seals.
Mixing up hot and cold stems or cartridge orientation—note left/right and alignment tabs.
Skipping valve seat inspection on compression faucets; a new washer won’t seal on a pitted seat.
Using thread tape where it isn’t needed. Many cartridge retainers are designed to seal on O-rings, not tape.
Scratching chrome with bare plier jaws.

When to call a pro

Shutoff valves are frozen, corroded, or leak when operated.
The faucet body is cracked, heavily corroded, or proprietary parts are unavailable.
Stripped threads, broken retaining clips, or a stuck cartridge that risks damaging the valve body.
Persistent leaks after correct part replacement.

Replacing wear parts restores most faucets to drip-free operation with basic tools. If your faucet is very old or parts are pricey, a full faucet replacement may cost $75–$250 for a quality unit plus 1–2 hours labor if hiring a plumber ($150–$300+). DIY replacement is very doable with a basin wrench and two supply lines.