What is the term for the undesirable reverse flow of water in a piping system?

The term for the undesirable reverse flow of water in a piping system is backflow. Backflow occurs when water in a system flows in the opposite direction than intended, which can lead to contamination of the water supply. This phenomenon is particularly hazardous in irrigation systems, where water may become polluted with fertilizers, pesticides, or other harmful substances that could enter the potable water supply if backflow occurs.

Backflow can be caused by changes in pressure within the system, such as a sudden drop in pressure due to a water main break or the use of water in one part of the system that creates a vacuum. To prevent backflow, systems often use backflow prevention devices, which are important safeguards in irrigation and plumbing to maintain the integrity of the water supply and ensure public health.

The other terms, while related to water flow and system pressure, do not specifically denote the reverse flow of water. Back pressure refers to a situation where the pressure in a portion of the system is greater than the pressure in the supply line, which doesn't necessarily imply reverse flow. Cross connection is a type of plumbing connection that could lead to backflow but is not the term for the reverse flow itself. Water hammer is a pressure surge that occurs when a fluid in motion is forced to