I did some work at a hospital that was right on the border betwene the 2 towns that shared it and was hooked up to both water mains.
They never tested the fire pump at full output for more than a few minutes because it would actually suck the water out of the mains so fast that both towns would end up with a 'boil order' due to the lowered pressure in the mains.
I never figured out how they managed to get fire insurance without someone making them put in a water tower...
