Drip irrigation is an irrigation system that uses plastic pipes to carry water to plants using low pressure. These systems can be underground or above ground according to a gardener's needs. According to Colorado State University, drip irrigation is more than 90 percent efficient, in comparison to a sprinkler system, which is only 50 to 75 percent efficient. One of the few things that affects this efficiency is the tendency for water to flow backwards through the system. This is called back flow, and is easily prevented.
Purchase a back flow prevention valve from your local hardware store or from an online irrigation dealer. Be prepared to give the model of your irrigation system valve, as although most back flow prevention valves come in a standard size, some are a bit more complex and require a different size.
Remove the irrigation hose from your outside water source using your wrench and check the diagram on the prevention valve packaging. Check the connection direction before placing it on the irrigation system hose.
Attach the prevention valve to the spigot in the correct direction, then connect the drip irrigation hose to the back flow prevention valve. Tighten the system using your wrench.
Turn on the water and check for proper flow, and that the system is free of leaks.