I have normal water pressure throughout the house except in one bathtub/shower. It takes forever for the tub to fill. The sink in that same bathroom is fine. I have no access to the water supply to the tub. I have not showered in that bathroom but was told the shower pressure was poor also. What do you suggest? Please advise. :confused:

Maybe the problem is an obstruction in the cartridge in the shutoff.

Obtain a rebuild kit and try it out. They aren't expensive.

Let us know if this helps.