David E. Ross wrote:

My neighborhood is on a water system that is gravity-fed from a
1,000,000 gallon tank up on a hill higher than any house.

That's typical.

The pressure in my lines is high enough that a hose turned on full
will writhe and snap like an injured snake.

Is "injured snake" some new water company standard?

Your water company like every other US water company is delivering
residential properties no more than about 40 psi, with volume limited
by meter diameter. Most folks on private wells will have much greater
pressure and volume than what a municipal water company supplies
residential customers... you'd be doing good if your tap can produce
four gallons a minute. With most neighborhoods on a municipal water
system it's suggested to run automatic sprinkler systems during the
wee morning hours before people awaken for the day, and then to have
no more than 4-5 sprinkler heads per zone.