So I was in meetings all day in a skyscraper near Times Square, and while admiring the view, I noticed the plethora of water towers that dot the skyline.
(See all those cylinders on the rooftops?)
It turns out, that the reason they are on top of all these buildings is because the water pressure doesn’t reach above 6 stories on it’s own. So they have pumps pump the water to the tower(s) on the roof, and it is distributed throughout the building from there.
They are mostly made of wood, and apparently there are only 2 companies that make them. That’s a good business to be in!