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Faucet Dripping When Turned Off? How to Find the Cause and Fix It

A faucet that drips from the spout after you close it has a seal that no longer seals. Which seal depends on the faucet type: most single-handle faucets made in the last 20 years use a cartridge, while older two-handle faucets use rubber washers. A drip once a second wastes about 3,000 gallons a year.

Verdict: DIY

Very doable. The hard part is identifying your faucet and buying the right cartridge.

Time
30–90 min
Cost
$10–50 in parts

Likely causes and how to tell

  • Worn cartridge (single-handle faucets)

    The handle moves up/down and left/right. Replacement cartridges are brand-specific: Moen 1225, Delta RP-series, etc.

  • Worn washer or O-ring (two-handle compression faucets)

    Separate hot and cold handles that tighten down with several turns. The drip gets worse if you don't crank the handle hard.

  • Worn valve seat

    A new washer stops the drip only for a few weeks. The brass seat under the washer is pitted.

  • Mineral buildup

    White crust on the aerator and around the spout; common with hard water.

How to fix it

  1. 1

    Identify the brand

    Look for a logo on the handle, base or escutcheon. Take a clear photo of the faucet; the brand decides which cartridge you need.

  2. 2

    Shut off the water

    Close both supply valves under the sink and open the faucet to drain pressure. Put a towel in the sink so small parts can't fall down the drain.

  3. 3

    Remove the handle

    Pry off the decorative cap, remove the screw (often a 2.5 mm or 3/32" hex), and lift the handle off.

  4. 4

    Pull the cartridge or stem

    Remove the retaining clip or nut and pull the cartridge straight up with pliers. Take it to the store to match it exactly.

  5. 5

    Install the new part

    Grease new O-rings with plumber's silicone grease, push the cartridge in the same orientation (hot on the left), and reinstall the clip.

  6. 6

    Reassemble and test

    Turn the water back on slowly and check both hot and cold. If hot and cold are reversed, rotate the cartridge 180°.

What you'll need

  • Replacement cartridge or washer kit
  • Hex key set
  • Phillips screwdriver
  • Needle-nose pliers
  • Plumber's silicone grease
  • Towel

Call a pro if

  • The shutoff valves under the sink don't work or are seized.
  • The cartridge is stuck and won't come out after removing the clip (you can crack the faucet body).
  • Water is leaking under the sink or from the base, not just the spout.

AI Handyman writes a free job brief in trade language, so a pro can quote from your photos.

Questions people ask

Should I replace the whole faucet instead?

If the faucet is under 15 years old and you can find the cartridge, repairing costs $20–50 versus $120–300 for a new faucet plus installation.

Are faucet cartridges covered by warranty?

Moen, Delta and several others offer lifetime warranties on cartridges. Call the maker with the model number; they often ship one free.

Related fixes

General guidance, not a licensed inspection. Follow local codes; when in doubt, call a licensed professional.