What Is an Overflow Pipe?

Overflow pipes are large pipes that make it possible to discharge surplus liquid from tank or other storage device without causing any damage. An overflow pipe is sometimes simply a means of preventing the storage container from overflowing by creating a channel for excess amounts of liquid to be redirected to another container or discharged into a river or lake. At other times, the pipe is part of a safety system that can quickly be opened to allow fluid to be extracted from a storage device when some type of structural fault is detected. This makes it possible to repair the fault, then refill the tank or cistern once the container is safe to use once again.

It is possible to find a water overflow pipe in many different types of devices. One common use of this type of safety pipe is found in toilet tanks. The presence of the pipe makes it possible to prevent the water in the tank from overflowing, thus averting the flow of the water out of the tank and onto the surrounding bathroom floor. From this perspective, the pipe helps prevent accidents that could take place, such as people slipping on the wet floor when entering the space.

The same general concept is found with a water heater overflow pipe or boiler overflow. In both cases, the idea is to safely discharge liquids from the holding tank so that the pressure inside the tank is kept at safe levels. This helps to minimize the potential for damage to the storage containers within a boiler system or a water heater, extending the life of the devices. At the same time, the release of pressure that is provided by the overflow pipe also prevents the possibility of injury to anyone in close proximity to the devices, since the potential for breakage due to excessive pressure is eliminated.

Depending on the type of liquid involved, an overflow pipe may direct the excess liquid into some type of purification device, route the liquid back into an existing plumbing or sewer system, or even discharge the liquid into a river or lake. Many jurisdictions have specific regulations on how overflow systems must be designed, and what must be done with any liquids that are discharged using these systems. In situations where the liquid does not require purification and poses no threat to the environment, the pipe may lead to an open channel of water. In other situations, the liquid is routed into a sewer system and is eventually processed through a municipal purification system for future use.