A water tower supplies water to a small community of 800 homes. The level of the water in the tank is $120 \mathrm{ft}$ above ground level, and the water main from the tower to the housing area is 1 mile of Sch. 40 commercial steel pipe. The water system is designed to provide a minimum pressure of $15 \mathrm{psig}$ at peak demand, which is estimated to be $2 \mathrm{gpm}$ per house.

(a) What nominal size pipe diameter should be used for the water main?

(b) If this size pipe is installed, what would be the actual flow through the main, in gpm?