science, water storage tanks?

Question

water storage tanks are usually built on towers or placed on hilltops. Why?

Answer 1

Storage tanks are usually put on high places to provide for necessary pressure for the water to flow into lower places. I'm assuming the water resevoir you are seeing doesn't have active pumps to pump the water into pipes and homes. If there is, then the tank doesn't necessarily need to be elevated. If there are no pumps though, the water needs to be up high. Gravity and weight of the water column leading down from the resevoir provides pressure on the water at the base of the column. That's what forces it to flow through the pipes going into homes.

If there's no pressure on the water, it wouldn't flow very well when you turn on the faucets.

Answer 2

Water tanks are on an elevated tower or hill to provide for adequate water pressure to the water system. Earth's gravity along with the height of the tank give the "head" pressure to the city water mains and eventually to the customer. For this reason, no service pumps are required to serve the individual dwellings and businesses. The city or water company maintain large pumps which are located at the source of the water (where the treatment is done) so that water can be pumped into the elevated tank. Without the tank in this elevated position, individual water pressure would vary according to location moreso than it does now. Also, this type system allows for easier and less complicated maintenance of pumps.

Answer 3

Elevated water tanks have several functions. They help maintain a stability to the water system by creating additional sources of pressurized water. Their storage capacity reduces the need for additional pumping capacity during peroids of high usage. They provide a large volume of emergency water supply as may be needed for fire fighting.
Tanks are mounted on towers where there are no hills high enough to provide the hydraulic pressure needed in the underground piping. The tanks have are filled by the normal operation of the system pumps during times of low usage. An "altitude valve" in the tank shuts off the filling flow line to prevent overflow, but the arrangement lets the water flow out if needed.
A description of "NPSH" is a misused term which has to do with the prevention of cavitation in pumps operating with inadequate suction pressure. In the case of cold water these would be pumps operating with a "suction lift' or a vacuum. The elevated tanks are on the pressurized discharge side of the pumps, not the suction.

Answer 4

Water in the water storage tank needs pressure to flow into, usually we adopts a pump to provide the required pressure, but when there is not a pump, we can built the tank is high position to solve this problem. For example, we often install the residential water tank on the roof of building.

Answer 5

The height is to provide what is known as "head pressure". Net Positive Head (NPH) is the vertical distance from the water level to the dispensing point. This will eliminate the need for pumps to provide positive pressure at the point of dispense. Net Positive Suction Head (NPSH) is used to calculate the size of a pump required to deliver a certain flow at a certain pressure of a certain fluid, uphill and considering friction loss from the piping system. This is when the water level is near, equal to or lower the the point of dispense.

Answer 6

Gravity allows the water to go down the hill... that's it basically. If it was at the bottom of the hill it would require motor power to get it to the top again if it was needed.