I live in a 6 year old house with 2.5 baths. Both showers are upstairs and the water pressure in one of the showers is very low, whereas in the other (right above the water heater in the garage) pretty high. Pressure elsewhere in the house is acceptable. Recently, water stains showed up on the tiles in the shower with the higher pressure. I had to "seal" the grout around the tiles and caulk after replacing the spigot's washer in this shower. However, in the process I realized that the shower pressure in this bathroom is so high that pretty soon, there will probably be another "internal" leak as the spigot's washer begins to disintegrate under the high pressure and allows the water to start creeping in behind the tiles.
Is there a prudent way for me to reduce the pressure in this shower and also increase the pressure in the other shower where it is pretty low?