When must vacuum breakers be installed on a water heater?

Vacuum breakers are essential devices that prevent backflow and protect water supply systems from contamination. They are typically required to be installed on water heaters to ensure that no contamination occurs, especially under specific conditions.

In this case, when the cold supply is near the bottom of the tank, there is an increased risk of back siphonage, which can draw potentially contaminated water back into the clean supply line. Installing a vacuum breaker in such situations prevents this risk by allowing air to enter the line if a negative pressure (vacuum) is created, thus stopping any backflow of water from the tank.

This installation is crucial, as backflow can lead to health hazards by mixing potable water with non-potable water. Ensuring that vacuum breakers are used appropriately in relation to the positioning of supply lines and tanks is an integral part of plumbing safety standards.