What is the primary purpose of surge tanks?

Surge tanks are primarily designed to control water hammer in a water distribution system. When there is a sudden change in water flow—such as when pumps are turned on or off, or when the valves in the system are rapidly closed—pressure surges can occur, leading to potential damage in pipes, fittings, and equipment. Water hammer results from these rapid pressure changes, which can create strong shock waves in the piping system.

Surge tanks act as pressure buffers or dampeners. When a pressure surge occurs, the surge tank can absorb the excess pressure, reducing the amplitude of the pressure wave and preventing it from causing damage. By allowing for some expansion of water and accommodating sudden changes in flow, surge tanks help maintain system stability and integrity.

The other options—such as increasing water temperature, storing excess water, and preventing flooding—do not align with the principal function of surge tanks, which is primarily focused on pressure control and mitigating transient pressures in the system.