What will it take to get us to come together and see eye to eye on things?
It's a static water pressure system. If you turn on one or two the system maintains pressue, but if you turned on all the hydrants in a town or city they would have no pressure. They use the same system as single family homes and businesses, they simply have no pressure reducers on the tap and a larger tap diameter.
I have seen one nearby that looked kinda like a brewery with the big ol tanks, but it pressurizred and said it was highly dangerous
fire hydrants are placed on pressurised water main pipes undeground and are placed in convenient spots for fire brigades to gain access in built up areas at suitable distances from each other. the water main pressure is kept up via pumps. the covers on hydrants are clearly marked to save confusion with other services. when a hydrant needs to be used it can be opened by way of a large metal key and a special reinforced hose can be connected and the pressure will drive water through this hose to the area that requires the water,usually a fire. when the operation is over the same key will turn off the hydrant and the hose can be disconnected.
A longer answer is in the description of the fire triangle:
