A height of 28 inches or 2 feet 4 inches is standard for valves in bathtub shower units.
Shower valve height from floor.
Employ your helper to hold the fixture at an estimated height and then see if it s a comfortable reach for all users.
Included in the many details are the requirements for showers and proper shower valve placement.
I find if you have a shower valve fitted over the bath then 1300mm off the floor is a good height.
Install faucets at the same height as the valve equidistant from the valve.
If your shower is also a bathtub ensure that the valve is low enough for bathers to use it but you can place it around 45 inches from the ground if the shower does not include a bathtub.
Check local building codes looking up local building codes is a great starting point if you want to install your shower valve at the right height.
For shower stalls install the valve at the standard height of 48 inches or 4 feet.
Height above floor the minimum height for the shower controls area is 38 inches above the floor.