Replacing a cartridge is a reasonable first repair for most people. The situations below are the ones where it stops being one, and where continuing is likely to cost more than calling someone.
Stop and call a plumber if
- The shutoff valves under the sink will not turn, will not fully close, or start dripping when you turn them. Old stops fail when disturbed, and a failed stop means the water cannot be controlled at the faucet.
- You cannot find the shutoff valves or the house main.
- Anything is corroded, cross-threaded, or will not loosen with moderate force. Forcing a stuck nut on a faucet body or a stuck cartridge can crack the body, and then the whole faucet is replaced.
- Water is coming from under the sink rather than from the faucet. That is a supply line or connection, not a cartridge.
- You removed the cartridge and something fell into the faucet body or the wall.
- The faucet is in a wall (a shower valve) and the cartridge will not come out with the manufacturer’s puller. Shower valves are soldered into the wall; damage there is expensive.
- The faucet is under a warranty or a home warranty plan that covers labor. Check first; it may be free.
- You have a tankless water heater or a recirculating system and the symptom is temperature swings rather than a drip. Those are often not faucet problems.
What to tell the plumber
The brand and model if you have them, the symptom, and what you have already done. If you have already taken the handle off and identified the cartridge, say so; it shortens the visit. Ask whether they will use the manufacturer’s part or a generic, and whether the manufacturer’s free warranty part can be used.
What a plumber visit usually costs
A cartridge replacement by a plumber is typically a one hour service call, often with a minimum charge. Prices vary a lot by region, so get the rate before they come. The part itself is usually $15 to $75, or free under warranty.