Gpf 3 : Symbol for U.S. gallons per flush, a specification sometimes found on toilets. 1 gpf = 3.785 liters per flush (Lpf). U.S. government regulations now require the use of low-flush toilets of 6.0 Lpf = 1.585 gpf or less
Russ Rowlett (Director), How Many? A Dictionary of Units of Measurement, Center for Mathematics and Science Education University of North Carolina, USA 2005. http://www.unc.edu/~rowlett/units/dictA.html, (Unit of Meas and Covr Factors - Amer) {608}