I have another plumbing problem, leaking kitchen faucet, leaks even when the water is turned off - what could cause that?

Usually, it a worn out washer. You will have to replace it. Or, if it is newer faucet, you will have to replace entire cartridge. Nothing unusual, just regular maintenance. If you are reasonably handy, and have basic tools, you could make the repair yourself. Otherwise, you will have to call handyman, or plumber, to do it for you

Hope that helps

Milo

Depends on the faucet. Single handle? Old? If so could just be a washer. Delta single handle? Probably just the cup seal. What brand? Most are easy fixes, some of the European styles more difficult.

Please tell us the brand and model number of your faucet that will determine how to fix the leak, Thanks.

John