Is a backflow preventer necessary?

Backflow preventers are required by almost all municipalities and building codes in Canada. These requirements may vary in type of backflow prevention. You should consult your local bylaws and building codes. The Capital Regional District (CRD) requires that irrigation systems have a Double Check Valve Assembly (DCVA) – a type of testable backflow preventer. Backflow preventers stop any contaminants that may breach your irrigation systems, such as fertilizers, from flowing back into the main water supply from your irrigation system.