If you're unsure if this Backflow Device is for you; click here WARNING! Irrigation systems supplied by domestic or private potable water systems are considered to be a potential pollution hazard to the water supply. These systems must include protection to prevent possible backflow of irrigation water into the potable water supply. Federal law requires a proper backflow device to be installed on any watering system to prevent contamination of the supply; whether it be pump or city water. Check your local water authority for installation requirements & codes. In many rural areas; specific requirements for landscape irrigation systems may not be covered in local plumbing codes and/or enforcement may be limited. HOWEVER...limitation in local authority does not alter the basic requirement for protection of the potable water supply.
Double check assemblies are not approved for backflow prevention of any toxic substance (liquid; solid; or gas).
A double check assembly consists of two spring loaded check valves; shut off valves on the inlet and discharge side of the check valves and small test cocks. Check valves allow water to flow in one direction only. A 12 inch minimum clearance is recommended under the assembly.