I have a shower tub combine and just recently when I turn the middle knob to shower the water still runs in the tub as well so its like your taking a shower bath at the same time
How can I fix it and will it cost a lot?:)

I have a shower tub combine and just recently when I turn the middle knob to shower the water still runs in the tub as well so its like your taking a shower bath at the same time
how can I fix it and will it cost a lot?:)
This shouldn't be costly at all. Sounds like you need a new washer on the diverter stem,(see image)Leave both hot and cold shut off and remove the stem and washer assemblyfrom the valve. Take it int5o a plumbing shop and have them replace the washer. Before you reassemble check the seat for nicks and rough spots and if the washer comes out in pieces turn the water back on for a few seconds to flush everything out. Good luck, Tom