Bioswales and constructed wetlands are under increasing use to address pollutants in storm water runoff. However, many installations of these BMPs have failed or have not been as successful as hoped. This interactive online course provides a discussion of the concepts of biofilters. Most of the failures can be attributed to insufficient information being available or to bad or no expert input into the design, construction, vegetating, or maintenance of the bioswale or constructed wetland. This course is intended to provide information on the design and use of biofilters so that designers will be able to make better decisions on the design, construction, implementation, and maintenance of these Best Management Practices.