A dripping faucet is caused by a worn part inside it: a washer in older compression faucets, or an O-ring, seal or cartridge in newer single-handle and cartridge faucets. Replacing that part usually stops the drip. If the faucet is corroded or parts aren't available, replacing the faucet makes more sense.
Reviewed by Ron Olsen, Master Plumber, certified in Washington
Why Faucets Drip
- Worn washer
- Common in 2-handle compression faucets. The rubber hardens and stops sealing.
- Worn cartridge
- Single-handle faucets use cartridges that wear out over time.
- Damaged O-ring or seals
- Cause leaks around the handle or the base of the spout.
- Corroded valve seat
- Mineral buildup and corrosion keep the faucet from sealing.
What You Can Safely Check
- Close the shutoff valves under the sink.
- Plug the drain so small parts can't fall in.
- Note the faucet brand. Take the old part to the store to match it.
- Replace the washer, O-ring or cartridge, and reassemble without overtightening.
When to Call a Plumber
Call a plumber if the shutoff valves won't close, if parts are seized or corroded, if the drip continues after new parts, or if water is leaking under the sink.
The repair is usually part of faucet & fixture repair, which explains what the plumber does and what affects the cost.
Hard Water Scale by City
What our city pages say about hard water scale:
- Ashburn, VA: Scale builds in tanks, tankless units and fixtures.
- Garland, TX: At 7 to 10.5 grains per gallon, scale builds in water heaters and stiffens valves.
- Lincoln, NE: At about 11 grains per gallon, scale builds up in water heaters, fixtures and appliances.
- St. Joseph, MO: At about 13 grains, scale builds fast in heaters, faucets and valves.
- Los Angeles, CA: Hardness above 7 grains per gallon in most of the city leaves scale in water heaters, tankless units, faucets and shower valves.
- Noblesville, IN: Water above 22 grains per gallon clogs aerators, ruins heating elements and fills tanks with sediment.
- Spokane, WA: Aquifer water at roughly 6 to 10 grains per gallon leaves sediment in tanks over time.
- Madison, WI: At 18 to 20 grains per gallon or more, scale builds in water heaters and softeners work hard. A failed softener shows up quickly as spots and stiff fixtures.
Dripping Faucet Questions
Is a dripping faucet worth fixing?
Yes. Even a slow drip wastes a meaningful amount of water over a year, and the repair is usually simple.
Why does my faucet drip after I replaced the washer?
The valve seat may be worn or corroded. It may need to be resurfaced or replaced, or the faucet replaced.