Our handyman tried to install a new faucet in our kitchen sink, but the supply lines to the new faucet are leaking from the back. The shut-off valve is 3/8" but the supply lines are 5/8". He tried to use a reducer but that didn't help. Do you think that replacing the shut-off valve will fix the problem?

Hi bbclarke97

Hard to say... could be an issue with the supply tubes and therefore changing the shut-off valve would fix nothing, right? If you want to continue to try to fix this on your own, I'd suggest stopping by a dedicated plumbing supply store and ask them to give you the proper transition fittings. If you or the handyman can't figure it out after that then your best bet is to hire a plumber... he/she will know exactly what to do and should resolve issue quickly.

Mark