This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (September 2011)

Louisville Water Tower, one of the few remaining standpipe water towers in the United States. It was completed in 1860.

The Water Tower of Aalsmeer, the Netherlands was completed in 1928 in an Art Deco style.

A water tower is an elevated structure supporting a watertank constructed at a height sufficient to pressurize a water supply system for the distribution of potable water.

Pressurization occurs through the hydrostatic pressure of the elevation of water; for every 10.20 centimetres (4.016 in) of elevation, it produces 1 kilopascal (0.145 psi) of pressure. 30 m (98.43 ft) of elevation produces roughly 300 kPa (43.511 psi), which is enough pressure to operate and provide for most domestic water pressure and distribution system requirements.

Many water towers were constructed during the Industrial Revolution; some are now considered architectural landmarks and monuments, and may not be demolished. Some are converted to apartments or exclusive penthouses.^{[citation needed]}

In certain areas, such as New York City in the United States, smaller water towers are constructed for individual buildings. In California and some other states, domestic water towers enclosed by siding (tankhouses) were once built (1850s-1930s) to supply individual homes; windmills pumped water from hand-dug wells up into the tank.

In 2009, the USDA announced that the largest man made water tower is located in McBee, South Carolina and holds 1,200,000 US gal (4,500,000 l) of water. This water tower was built and is operated by Alligator Water and Sewer.^{[citation needed]}

Construction[link]

A variety of materials can be used to construct a typical water tower; steel and reinforced or prestressed concrete are most often used (with wood, fiberglass, or brick also in use), incorporating an interior coating to protect the water from any effects from the lining material. The reservoir in the tower may be spherical, cylindrical, or an ellipsoid, with a minimum height of approximately 6 metres (20 ft) and a minimum of 4 m (13 ft) in diameter.^{[citation needed]} A standard water tower typically has a height of approximately 40 m (130 ft).

Purpose[link]

Shooter's Hill water tower is a local landmark in London, United Kingdom. Water towers are very common around London suburbs.

The users of the water supply (a town, factory, or just a building) need to have water pressure to maintain the safety of the water supply. If a water supply is not pressurized sufficiently, several things can happen:

• Water may not reach the upper floors of a building;
• Water may not spray from a tap with sufficient flow
• Without a water tower, parts of gravity flow water supply systems in hilly areas may be subject to negative pressures (see siphon). Negative pressure in the system may cause shallow groundwater to be pulled into a leaky water supply system, polluting it with microorganisms, dirt, sand, fertilizers, and any other toxic contaminants that may be in the groundwater;

Water towers are able to supply water even during power outages, because they rely on hydrostatic pressure produced by elevation of water (due to gravity) to push the water into domestic and industrial water distribution systems; however, they cannot supply the water for a long time without electricity, because a pump is required to refill the tower. A water tower also serves as a reservoir to help with water needs during peak usage times. The water level in the tower typically falls during the peak usage hours of the day, and then a pump fills it back up during the night. This process also keeps the water from freezing in cold weather, since the tower is constantly being drained and refilled.

Operation[link]

How a water tower works:
1. Pump station
2. Reservoir
3. Water user

The height of the tower provides the pressure for the water supply system, and it may be supplemented with a pump. The volume of the reservoir and diameter of the piping provide and sustain flow rate. However, relying on a pump to provide pressure is expensive; to keep up with varying demand, the pump would have to be sized to meet peak demands. During periods of low demand, jockey pumps are used to meet these lower water flow requirements. The water tower reduces the need for electrical consumption of cycling pumps and thus the need for an expensive pump control system, as this system would have to be sized sufficiently to give the same pressure at high flow rates.

Very high volumes and flow rates are needed when fighting fires. With a water tower present, pumps can be sized for average demand, not peak demand; the water tower can provide water pressure during the day and pumps will refill the water tower when demands are lower.

Using wireless sensor networks to monitor water levels inside the tower allows municipalities to automatically monitor and control pumps without installing and maintaining expensive data cables.^[1]

Decoration[link]

The House in the Clouds in Thorpeness functioned as the town's water tower from 1923 until 1977.

Water towers can be surrounded by ornate coverings including fancy brickwork, a large ivy-covered trellis or they can be simply painted. Some city water towers have the name of the city painted in large letters on the roof, as a navigational aid to aviators and motorists. Sometimes the decoration can be humorous. An example of this are water towers built side by side, labeled HOT and COLD. Cities in the United States possessing side-by-side water towers labeled HOT and COLD include Granger, Iowa, Canton, Kansas, and St. James, Missouri (Eveleth, Minnesota at one time had two such towers, but no longer does^[2]). When a third water tower was built next to the Okemah, Oklahoma set of Hot and Cold towers, the town briefly considered naming it "Running", but eventually decided to use "Home of Woody Guthrie". The House in the Clouds in Thorpeness, located in the English county of Suffolk, was built to resemble a house in order to disguise the eyesore, whilst the lower floors were used for accommodation. When the town was connected to the mains water supply, the water tower was dismantled and converted to additional living space.

Sapp Bros. truck stops use a water tower with a handle and spout – looking like a coffee pot – as the company logo. Many of their facilities have decorated actual water towers (presumably non-functional) on-site.

The first and original "Mushroom" – Svampen in Swedish – was built in Örebro in Sweden in the early 1950s and later copies were built around the world including Saudi-Arabia and Kuwait.^{[citation needed]}

Many small towns in the United States use their water towers to advertise local tourism, their local high school sports teams, or other locally notable facts.^{[citation needed]} Since the water tower is sometimes the highest point in the town, antennae, public address systems, cameras and tornado warning sirens are sometimes placed on them as well.

Many water towers serve manufacturing and other commercial facilities. These are often decorated with the name of the company that the water tower serves.

Water Towers around the World[link]

This section requires expansion.

Water towers are ubiquitous in the New York City skyline, United States.

In the 19th century, New York City required that all buildings higher than six stories be equipped with a rooftop water tower. This was necessary to prevent the need for excessively high pressures at lower elevations, which could burst pipes.^{[citation needed]} In modern times, the towers have become fashionable in some circles. As of 2006^[update], the neighborhood of Tribeca requires water towers on all buildings, whether or not they are being used.^{[citation needed]} Two companies in New York build water towers, both of which are family businesses in operation since the 19th century.^[3]