Within the cornbelt of the U.S. the use of subsurface drainage systems has been important and perhaps essential in the development of the current agricultural production systems. How water is managed relative to subsurface drainage not only impacts crop production but can also impact the quality and quantity of the water leaving the agricultural field. As a result it is important to understand how subsurface drainage implementation, design, and management may impact crop production and water. This paper and presentation will discuss how subsurface drainage works, how drainage design relative to drain sizing and spacing may impact crop production, and how new technologies for managing drainage water may provide both production and water quality benefits. In addition, some of the commonly held myths about subsurface drainage will be discussed.