If you are experiencing low water pressure in just one shower (both hot and cold water) and water pressure is fine everywhere else in your house, then the shower head might have blockage. This is often caused by sediment (sand) in pipes for new construction houses leading to a blocked shower head, or a faulty / damaged gasket, or mineral deposit build-up. In order to diagnose and fix the problem, you will need to remove the shower head. To disassemble the head you need to remove it from the shower pipe using a pair of padded pipe wrenches to avoid scratching the chrome. One wrench is used to hold the shower pipe steady while turning the attaching joint.
Sediment buildup: Simply rinse out all sand/sediment from shower head. Be careful to also thoroughly rinse the joint threads so that no grains of sand remain and to ensure a tight seal. Use a toothpick to carefully remove debris stuck inside tiny holes or ridges.
Faulty gasket / damaged o-ring / remove water saver feature: If the gasket is damaged replace with new. Some shower heads come with water saver gaskets. Sometimes these gaskets can be removed to increase water pressure. If the gasket cannot be replaced then purchase a new shower head.
Mineral Deposits: Soak the shower head in undiluted white distilled vinegar overnight to loosen deposits and use stiff brush to scrub the showerhead. Use a toothpick to remove debris from small holes.
Undiluted white distilled vinegar can be used for coloring easter eggs - canning - pickling - marinating - removing beer stains, remove grass stains, candy stains, coffee stains, deoderant stains, removing human urine smell, feces stains, remove cat urine smell, mustard stains, remove rust stains, sweat stains, tea stains, remove urine stains and for cleaning shower heads to remove blockage.