An extensive selection of water/energy efficient shower heads are available for hospitality and institutional application. Flow rates do not exceed 2.0 gpm and will realize a 20 - 30 % water savings as compared to conventional 2.5 gpm models.  Manufacturers of the many styles available include
Earth, Whedon, Oxygenics, Chatham, Speakman and Sloan.
 

A full 7.5 inch shower head designed with 54 powerful spray nozzles creating an unbelievable downpour. 
The "Storm" uses less than 2.0 gpm

Is your showerhead in good shape and functional?
Try these low cost solutions in your present shower devices.