How Water Dept's of major metros maintain water pressure?

[bluemoonKY]

Small towns in America frequently have water towers in which water is kept in huge tanks hundreds of feet high within water towers. I suppose that some sort of pump pumps the water entering the water tower to the tank at the top. I suppose that water pressure is maintain in these small towns by the force of gravity. Since the water tank is hundreds of feet high, gravity would keep water pressure on all the water lines going to all the houses of businesses in the area.

However, I don't believe that the Water Departments of major metropolitan areas in America such as Los Angeles, New York City, or Chicago, maintain water pressure using water towers in the same way that small towns do. Why do I not think that the Water Departments of major metropolitan areas use the same type of water towers to maintain water pressure that small towns use? I have never heard or seen such a thing. If, say, the Water Department of the City of Chicago used the same types of water towers that small towns use, it would require many many dozens of water towers. I never see those multi-hundred feet tall water towers with a tank at the top in major metropolitan areas. Therefore, I think that such water towers don't exist in major metropolitan areas.

How do the Water Departments in major metropolitan areas in America maintain water pressure to go to all the houses and businesses in a major metropolitan area?

 

[TeethWhitener]

I have never heard or seen such a thing.

https://www.google.com/search?biw=1.....1.1.64.psy-ab..1.4.177...0i24k1.WNKlmI3lHxU
Now you have. Almost every single multistory building in Manhattan has a rooftop water tower; some have many. I imagine it's the same with most dense cities. The NIMBY suburbs on the other hand, well, I don't know about that.

 

[bluemoonKY]

https://www.google.com/search?biw=1.....1.1.64.psy-ab..1.4.177...0i24k1.WNKlmI3lHxU
Now you have. Almost every single multistory building in Manhattan has a rooftop water tower; some have many. I imagine it's the same with most dense cities. The NIMBY suburbs on the other hand, well, I don't know about that.

But how does the Water Department in New York City maintain enough water pressure to ensure that the water in the water lines reaches the pumps that pump the water to the roofs of the multi-story buildings?

 

[scottdave]

You can find water tanks on top of high rise buildings, in some large cities. These usually are just for that building. One way to provide pressure is through the use of an expansion tank. Many small water companies utilize this, rather than erecting a tower.

 

[bluemoonKY]

You can find water tanks on top of high rise buildings, in some large cities. These usually are just for that building. One way to provide pressure is through the use of an expansion tank. Many small water companies utilize this, rather than erecting a tower.

But how does the Water Department in New York City maintain enough water pressure to ensure that the water in the water lines reaches the pumps that pump the water to the roofs of the multi-story buildings?

 

[Mech_Engineer]

Pressurized tanks and high-capacity pumps are also used to maintain water pressure in areas where water towers are prohibitive. See here:

https://en.wikipedia.org/wiki/Water_supply#Water_pressure

Pressure in an urban water system is typically maintained either by a pressurised water tank serving an urban area, by pumping the water up into a water tower and relying on gravity to maintain a constant pressure in the system or solely by pumps at the water treatment plant and repeater pumping stations./