Lawn (Turf) Irrigation Systems
For the protection of the water purveyor’s distribution system, all irrigation systems must have an approved backflow prevention assembly that is proportionate with the degree of hazard. The American Water Works Association (AWWA) classifies all irrigation systems connected to a public water system as a high health hazard and recommends an air-gap separation or a reduced-pressure principle backflow prevention assembly (RP) as the appropriate means of protection.
In some states, irrigation systems are categorized as either a high health hazard or a moderate health hazard as defined as follows:
High health hazard:
Any irrigation system that contains pumps or injectors for the addition of chemicals and/or fertilizers is considered a high hazard. This risk assessment is also based on the additional hazard posed by bacterial contaminants found on lawns, and on the possibility of changes being made to the irrigation system by the customer. An approved RP, or an approved air gap separation, should be required in all cases where chemicals or herbicides may be injected into the irrigation system, or where an auxiliary water supply is also provided for irrigation water.
Moderate health hazard:
All irrigation systems that are not classified as a high health hazard are considered to be moderate health hazards. This risk assessment is based on the hazard posed by bacterial and chemical contaminants found on lawns, and on the possibility of changes being made to the irrigation system by the customer. An approved double check valve assembly (DCVA), or pressure vacuum breaker assembly (PVBA), should be required. However, an approved PVBA does not provide adequate protection if it is subjected to flooding, backpressure, elevated piping, or if compressed air is used to winterize the irrigation systems. In these situations, an approved DCVA should be required as a minimum level of protection.
In states where the International Plumbing Code (IPC) has been adopted, DCVA’s are not considered an acceptable means of protection against backflow on irrigation systems. The IPC requires an atmospheric-type vacuum breaker (no valves can be installed downstream), a PVBA or a RP, with the RP being the required means of protection against backflow because chemicals are being introduced into the irrigation system. It should be noted that the above limitations always apply to the installation of PVBA’s.
Please contact one of our Cross Connection Specialists for help in determining which type of backflow prevention assembly is acceptable in your state.
WARNING: Installation of a backflow prevention device could cause thermal expansion resulting in potential serious bodily injury and/or property damage. When installing a backflow prevention device, you must consult with a professional plumber to protect against thermal expansion AND ENSURE ALL NECESSARY PRECAUTIONS ARE TAKEN. For more information on thermal expansion, please visit our Thermal Expansion section under Cross Connection Control and Backflow Prevention in this website.