While drip irrigation is relatively easy, information about drip irrigation is often more complicated and confusing than it needs to be. Well-meaning professors and engineers use terms like "head" and "flow rate" without explaining exactly what they mean and how they are used. And it's often difficult to get help planning a small farm system in states without large irrigated acreages and irrigation traditions. The purpose of this bulletin is to help farmers understand the simple calculations involved in designing a small drip irrigation system.