Drip irrigation systems are designed to work with low water pressure. When your water source emits high water pressure, it will be too much pressure for your system to handle. The solution the pressure regulator does the trick it lowers the water pressure and alleviates stress on your drip system. No more flying fittings or popping off emitters. The 3/4 in. FPT X 3/4 in. MPT pressure regulator comes preset at 30 PSI. Connects to 3/4 in. MPT pipe on one side (such as an existing underground irrigation system).