I'm doing calculations for how much water was lost during flushing a hydrant. It is a 2.5 in. outlet and the pressure is on the system in that zone is 40 psi. It was flushing for 1.5 hours. Q=AV V=[(2 dP gc)/density] density = 62.4 lb/ft^3 dP=40 psi gc=32.2 lbm ft / lbf s^2 V=77ft/s Q=AV=(0.0340)(77)=2.6 ft^3/s=19gal/sec The hydrant was flushing for 1.5hrs=90mins=5400secs so... The water lost was 19*5400=105,892.77 gals??? is that right?? can you check my generals theory of my problem?? it seems to me a little bit high to loose 100,000 gals in 1.5 hours for flushing a hydrant... don't you think?