Many thanks...(to ALL)...
Agreed. The energy required to lift the water is minuscule by comparison to the other energy factors. As you mentioned, heating water is one of, if not the, largest energy hogs...
However, my one gallon of water is not the sole issue, its everyone's one gallon. "Municipal planners assume each individual (regardless of whether or not it is a family) uses about 150 gallons of water a day."
http://wiki.answers.com/Q/How_much_water_does_the_average_American_family_use_in_a_day#ixzz16VcdjZ93
A 10,000 population city would then consume 15 million gallons of water each day. That's 225 gallons of gasoline per day per 10,000 population. Or, 82,125 gallons per year. Each flush of the toilet likely uses an average of 3 gallons of water. I'm guessing here, but each person likely flushes the toilet, what, four times a day? That same 10,000 population then goes through 120,000 gallons of water each day just flushing the commode; a paltry 1.8 gallons of gasoline equivalent per day just as a result of flushing the john. Cut the number of flushes in half and you can realize a potential savings in excess of 325 gallons of gasoline equivalent per 10,000 people per year. The population of the US is estimated to be 300,000,000; or 9.8 million gallons of gasoline equivalent per year. When you look at numbers in that perspective, the savings really adds up.
So...the conclusion is: regardless how tiny the energy savings is on an individual basis, the energy savings are significant across the entire population. Every joule counts; a joule saved is a joule earned...
When it's yellow let it mellow. When it's brown send it down.
Amuse toi bien and thanks to all who answered...