[Greenbuilding] reduced flow shower heads

[Reuben Deumling]

And then ther's the navy shower "button" or "soap valve," which is
installed between plumbing and shower head and allows one to interrupt
the flow of water for as long as desired and retrieve it at the same
hot/cold mix for rinsing off. It is my favorite conservation device.
Where I've lived a well made steel version is locally available for
less than $4--though sometimes one has to ask around.

http://en.wikipedia.org/wiki/Navy_shower