Backflow is the unwanted flow of contaminated water reversing into your clean potable water supply system. Backflow is typically caused when there is an abnormal drop in water pressure coming from your home and contaminate water is siphoned back into your clean water supply. This is typically referred to as back-siphonage and/or back pressure.

Check out Zurn’s backflow testing guide for a Zurn Wilkins 350 3/4 inch to 1 inch.