Operators of regulated MS4s are required to develop a stormwater management plan (SWMP) that includes measurable goals and to implement needed stormwater management controls (BMPs). The process of developing a plan, implementing the plan, and evaluating the plan is a dynamic, iterative process that helps move communities toward achievement of their goals. This fact sheet provides guidance to MS4's to assist in the examination and evaluation of the effectiveness of their stormwater management programs.