Trickle Valve Data

I am looking for research and data on the implementation of trickle valves or shower flow regulators in residential use. Any references or assistance would be appreciated. Below is a calculation i have made using information from various sources. If anyone can give me feedback on errors or suggestions, I would appreciate it.

Thank you,
Danny Kocurek
Arlington Conservation Council
Arlington, Texas

Average shower use 11.6 gallons/day
average shower water use is 6000 gal/year
estimate reduce water use by with trickle valve - 3000 gallons/year + water saved 3000 g/y X $0.0024/gal=$7.20/person = cost of water saved
The cost to heat 4,000 gallons of water from 65 F. to 135 F., in an electric storage-tank heater (88% efficient) at $.084/kWh, is $65.00 - $48.75=money saved in heating costs
Total savings by using trickle valve = $55.95 per person per year