1860
Louisville Water Tower
Imagine that you are designing the water supply for a small city. You have to get water to every home and business. To do that, you might start by laying out water mains—the big pipes, many feet (meters) in diameter—that act as the backbone of the water system.
A set of pumps pressurizes the water from the treatment plant and injects it into the mains. On the other side of the mains is the distribution network that, through smaller and smaller pipes, eventually provides a connection to every building that needs water.
But what happens during a power failure or a pump failure? Every water system leaks, and during a power failure the system will depressurize. All of those leaks start letting pathogens into the water system, counteracting the effects of water treatment. And then a fire will start somewhere—it’s part of Murphy’s Law. But there will be no water for fire hydrants, which also connect into the water system.
The engineering solution to both of these problems is the water tower. It is simply a big storage tank raised into the air on some kind of tower structure. The tank might hold a million gallons or more. The operation is extremely simple—a large pipe connects from the water main into the bottom of the tower. Pressurized water rises up the pipe and fills the tank.
If a power failure occurs now, gravity keeps the system pressurized. If a water tower is 200 feet (61 meters) tall, gravity will create 86 psi (592 kPa) of pressure from the water in the tank. As long as the tank has water, the system will have pressure. The tank can be sized to provide the community with hours of water so that pumps can be serviced, pipes repaired, etc.
Water towers also help to handle surges, for instance, in the morning, when everyone in town is taking a shower at roughly the same time. The pumps that pressurize the system don’t have to be quite as big. Louisville, KY, installed one of the country’s first water towers in 1860, and thousands have been built since.
SEE ALSO Roman Aqueduct System (312 BCE), Water Treatment (1854), Modern Sewer System (1859), Drip Irrigation (1964).
Louisville water tower, one of the remaining standpipe water towers in the United States.