An anti-backflow valve is exactly what is says, a shut-off valve which prevents polluted water from flowing back to the potable water supply.  It can come in industrial strength or residential strength, and it comes in a variety of designs and sizes, but the primary purpose, no matter which kind is used, is to protect

A 2 inch backflow preventer is a 2-inch bronze double check backflow device with two brass ball valves for easy shut-off and four ball valve test cocks. It is used to stop the flow of contaminated water should it reverse direction in a situation referred to as backflow. The backflow preventer keeps the water from

It hasn’t been all that long ago that a residential backflow preventer wasn’t required in city neighborhoods.  The main concern over backflow, it was believed, came from industrial and commercial facilities and not, it was believed, from residential homes. Then chlordane was siphoned through a hose at a residence in Roanoke, Virginia, contaminating the water