When installing a backflow preventer for lawn sprinklers, how high must it be above the highest sprinkler head?

The installation of a backflow preventer for lawn sprinklers is crucial to ensure that the potable water supply remains uncontaminated. The height requirement above the highest sprinkler head is set to prevent any potential back-siphonage or back-pressure problems that can occur when there is a drop in water pressure.

Typically, it is specified by plumbing codes that the backflow preventer must be installed at least 6 inches above the highest point of the sprinkler heads in the system. This distance provides sufficient clearance to prevent any chance of irrigation water, which could contain fertilizers, pesticides, or other contaminants, from flowing back into the potable water system in case of a pressure drop.

Meeting this height requirement ensures compliance with health and safety regulations and helps to protect the drinking water supply from contamination. The importance of this specification cannot be overstated, as proper installation is essential for the effective operation of the backflow prevention device.