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Fix a leaking faucet

We'll shut off the water, open the faucet, replace the worn seals or cartridge, and stop the drip.

How-to · Home plumbing
20–40 min
What you'll need
  • Hex key or screwdriver (to remove the handle)
  • Replacement O-rings, washers, or cartridge (match the model; check the old part)
  • Bucket and towels
  • Channel-lock pliers (if the cartridge is stuck)
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Steps

Goal: Shut off the water, open the faucet, and prepare the work area before disassembly.

Shut off the water

  • Turn both supply valves under the sink clockwise until they stop. If a valve is stuck or corroded, shut off the main house valve instead.
  • Open the faucet to confirm water stops flowing. You should see the stream slow to a trickle and stop within a few seconds.
  • Open both hot and cold handles (or the lever to center) to drain any water left in the lines. When the flow stops, check under the sink for residual dripping.
  • Set a bucket under the supply connections and lay towels around the base of the sink. If the cabinet floor is finished wood, add a plastic sheet first. Verify the bucket catches the direct drip path. You should see full coverage under every connection point.

Remove the handle

Goal: Expose the cartridge or stem so you can inspect and replace the seals.

  • Remove the decorative cap (pry with a flathead if needed). Unscrew the set screw with a hex key or screwdriver. If the handle is stuck, apply penetrating oil around the base and wait five minutes.
  • Pull the handle straight up to remove it. You should see the cartridge stem or valve body exposed.

Extract the cartridge

Goal: Remove the cartridge so you can inspect and replace worn parts.

  • Unscrew the retaining nut or clip that holds the cartridge in the faucet body. If the cartridge is seized, grip it with pliers and twist gently while pulling upward. If it will not budge with gentle pressure, stop and call a plumber—forcing it can damage the faucet body.
  • When the cartridge comes free, check the model number stamped on it. You should see the part released cleanly so you can match a replacement at a hardware store.

Inspect and replace

Goal: Identify worn O-rings, washers, or a damaged cartridge and replace them.

  • Check every O-ring, seal, and seat washer on the cartridge and inside the faucet body. Cracked, flattened, or grooved rubber is the likely cause of the drip.
  • Install new O-rings, washers, or a complete replacement cartridge that matches the original. If the valve seat inside the body is pitted, smooth it with a seat-grinding tool—or call a plumber if you don’t have one. If the seat is deeply pitted or rough after grinding, call a plumber.
  • When the new parts are in place, verify they sit flat with no gaps. You should see the seal aligned evenly against the valve body.
  • Good: New parts installed. Proceed to Reassemble and test.
  • Bad: Valve seat is badly corroded or the faucet body is cracked—see When to get help.

Reassemble and test

Goal: Put everything back in reverse order and verify the drip is gone.

  • Insert the cartridge and tighten the retaining nut. If you removed a retaining clip, press it back into its groove until it clicks. Wiggle the stem—nothing should feel loose.
  • Slide the handle onto the stem and tighten the set screw. Test the range of motion—smooth rotation from off to full open with no binding.
  • Open each supply valve a quarter turn at a time, starting with cold. If you hear hammering, close slightly and open more slowly. When both valves are fully open, check under the sink for drips. You should see no moisture on any fitting or supply line.
  • Run the faucet for five minutes at full flow, then close it. Check the spout for any drip over the next sixty seconds.
  • Good: Zero drips. The repair is complete.
  • Bad: Drip returns—recheck the seat washer or cartridge; the seat may need more work or replacement.

When to get help

Call a plumber if:

  • The valve seat is badly corroded or the faucet body is cracked.
  • You cannot shut off the supply valves (stuck or corroded)—shut off the main water supply first.
  • Widespread leaks appear under the sink after reassembly.
  • You have replaced the cartridge and it still leaks.

For other plumbing fixes, see How to shut off the main water supply, Fix a toilet that runs, or How to unclog a drain.

Verification

  • The faucet produces zero drips for at least sixty seconds after closing.
  • All supply connections under the sink are dry after five minutes of flow.
  • The handle operates smoothly through the full range of motion.

Are the supply valves under the sink off?

Turn both hot and cold supply valves clockwise. If stuck, shut off the main house valve instead.

Turn both supply valves under the sink clockwise until they stop. Open the faucet to confirm water stops. Good: water stops. Bad: valves stuck or corroded—shut off the main house valve or call a plumber.

Yes No

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Shut off the water

Turn both supply valves clockwise. If they will not turn, shut off the main water supply instead. Do not force stuck valves—call a plumber. When water stops, open the faucet to drain the lines.

Done

Have you removed the handle and extracted the cartridge?

Remove the decorative cap, unscrew the set screw, pull the handle. Unscrew the retaining nut to extract the cartridge.

Remove the handle (cap, set screw, pull up). Unscrew the retaining nut and extract the cartridge, ball, or stem. Check the model number on the old part to match a replacement. Good: cartridge is out. Bad: cartridge seized—grip with pliers, twist gently; if it will not budge, call a plumber.

Yes No

You can change your answer later.

Extract the cartridge

Unscrew the retaining nut or clip. If the cartridge is seized, grip with pliers and twist gently while pulling. When it comes free, note the model number for replacement. Place a bucket and towels under the work area first.

Done

Is the valve seat or faucet body corroded or cracked?

Inspect O-rings, seals, and washers. If the valve seat is pitted or the body is cracked, call a plumber.

Check every O-ring and seal. If any is cracked, flattened, or worn, that is the cause. If the valve seat inside the body is badly pitted or the faucet body is cracked, do not repair—call a plumber or replace the faucet. Good: only seals are worn—replace them. Bad: seat or body damaged—call a plumber.

Yes No

You can change your answer later.

Replace seals and reassemble

Install new O-rings, washers, or a replacement cartridge that matches the original. If the seat is slightly pitted, smooth it with a seat-grinding tool. Reassemble in reverse order. Turn supply valves on slowly. Run the faucet for five minutes, then close it. Check for drips over sixty seconds. Good: no drips. Bad: still drips—recheck seals or call a plumber.

Done

Call a plumber

Call a plumber if: supply valves are stuck; the valve seat is badly corroded; the faucet body is cracked; or you have replaced the cartridge and it still leaks. Replace the whole faucet if the body is damaged.

Done

Reviewed by Blackbox Atlas

Frequently asked questions

Why is my faucet dripping?
Usually a worn O-ring, washer, or cartridge. Shut off the supply valves, remove the handle, and inspect the seals. Replace any cracked or flattened parts.
Do I need to shut off the main water to fix a leaky faucet?
No. Shut off the hot and cold supply valves under the sink first. Only use the main house valve if the supply valves are stuck or corroded.
When should I replace the whole faucet instead of repairing it?
Replace if the valve seat is badly corroded, the faucet body is cracked, or you've replaced the cartridge and it still leaks. A plumber can advise.

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