 Today, I'm going to demonstrate a simple way to install backflow prevention between the faucet and a fertilization feeder. The backflow preventer or check valve is a critical piece of the irrigation system. The backflow preventer is true to its name. It prevents irrigation water from re-entering or backflowing into the water supply. Backflow, sometimes called back siphoning, occurs when there is a negative pressure or pressure loss on the supply side of the irrigation system. Without a functioning backflow preventer, there is a risk of contaminating the water supply. It is important to make sure that you install the backflow preventer in the correct direction. When installing it, make sure to look for the manufacturer's stamp directional arrow that is located on the side of the backflow preventer. The backflow preventer can be installed using a glue fitting as shown or as a threaded fitting depending on the model that is used. The arrow is the direction of water flowing through the pipe. If the backflow preventer is installed backwards, then it will stop the flow of water to your field. We hope this video was very useful. Please check out our video series to learn all the steps in installing a simple irrigation system on a small phone. Thank you.