I'd say it's a quite big one, "every city" has water towers to provide pressure to the people living in it, or they rely on the water source if it's higher up than the city.
There are probably exceptions, where this isn't true, but raised tanks make modern society possible.
Another good thing with water towers is that we can keep running the pumps at a lower RPM where efficiency than if we were trying to build a system with pumps to keep pressure.
Great channel if you're curious about everything related to humans relationship with water.
There are probably exceptions, where this isn't true, but raised tanks make modern society possible.
https://youtu.be/yZwfcMSDBHs more on water towers, which are raised tanks of water.
We also pump water into fake lakes to later extract electricity from it. (https://youtu.be/66YRCjkxIcg)
Another good thing with water towers is that we can keep running the pumps at a lower RPM where efficiency than if we were trying to build a system with pumps to keep pressure.
Great channel if you're curious about everything related to humans relationship with water.