Precautions are necessary to prevent contaminated water from entering your irrigation system. Bacteria and other microbiological contaminants may enter your system through malfunctioning valves or broken sprinkler heads and subsurface pipes. Water may also become chemically contaminated if you are applying or injecting fertilizer into your drip irrigation system.
Potential contamination from your irrigation system becomes a serious issue should backflow occur. Backflow is a flow reversal which may occur from a broken water main or from a flowing fire hydrant. In order to protect your home from backflow, an appropriate "backflow prevention assembly" must be incorporated into your irrigation system.
Properly installed and maintained backflow prevention assemblies will prevent contamination and are required by state and local laws.