Backflow Prevention on Sprinkler Systems

Atmospheric Vacuum Breaker

• Atmospheric vacuum breakers often are built into anti-siphon valves. Code requires each valve to be 6 inches higher than the highest sprinkler. This type is made for home systems, is made the cheapest and is the least reliable of all backflow prevention systems.

Pressure Vacuum Breakers

• Pressure vacuum breakers are made for home systems and are required to be 6 inches higher than the highest sprinkler by code. Only one pressure vacuum breaker is required per system.

Double-Check Backflow Preventer

• Double-check backflow preventers are made with two check valves in a row that prevent water from flowing back into the system. It is the only type to be installed below grade or underground.

Reduced Pressure Backflow Preventer

• Reduced pressure backflow preventers are used on commercial sites. These systems need to be installed 12 inches above grade but not above the highest sprinkler. It is designed for the most hazardous conditions and is considered the best.