if 5 psi [12' of head] @ 4.5 GPM is bad
40 PSI [92' of head] @ 16 GPM is good
then a single number figure of merit for resi. water supplies would be how much hp is available at a sillcock with nothing else running.
12 x 4.5/3956 = 0.014 hp
92 x 16/3956 = 0.37 hp
I don't know what WaCo's benchmarks are except for this 40 PSI and 16 GPM.
If anyone out there has pressure & GPM gauges I'd like to hear your values along with how satisfied you are with your city water supply. This will sharpen the line between a good resi. supply and a bad resi. supply.