Farmland drainage is an integral part of Iowa’s landscape and plays a critical role in its bio-economy. Production capacities of Iowa soils can only be optimized with well-designed and properly operating subsurface drainage systems. Features needing attention when designing and installing a new system or retrofitting an old one include drainage intensity (spacing and depth), drainage capacity (size and grade), water quality and quantity management (controlled drainage, shallow drainage, etc.), and the economics of payback. Iowa State University Extension & Outreach initiated the Iowa Drainage School in 2007 to educate stakeholders on subsurface drainage concepts customized to the upper Midwestern states. Three hundred thirty-five participants, consisting of contractors, engineers, drainage planners, land owners, farmers, agency staff, and drainage district supervisors, have attended the school. All participants completing the end-of-school evaluation have ranked the school good (45%) or excellent (55%) and reported making drainage decisions on over 1,100 acres per participant. A summary of participants’ preferred methods of surveying and developing topographic maps, methods of determining drainage sizing and spacing, and developing drainage maps is presented. This paper summarizes the nine-year outreach efforts of Iowa Drainage School in terms of what students learned in the school, how they have used the knowledge gained, and how they have applied what they learned in the drainage school.