Bioretention rain gardens are a popular strategy for capturing and storing stormwater while improving water quality by filterning pollutants. As a nutrient pollutant, phosphorus contributes to downstream algal blooms. If designed well, bioretention systems can be used to remove phosphorus from stormwater. A recent research project at the University of Vermont, with support from the EPA Office of Research and Development’s Regional Applied Research Efforts (RARE) program and Lake Champlain Sea Grant, explored the potential for drinking water treatment residuals (a byproduct of drinking water filtration) to bind phosphorus within bioretention soil media. In this webinar, speakers from the University of Vermont will discuss lessons learned from many years of research on bioretention soil media, including how different installation components can remove phosphorus from runoff or potentially leach phosphorus into outflows. Speakers will take a deep dive on the technical aspects, scientific results, and water quality impacts of different bioretention case studies. The presentation will cover the pros and cons of compost, drinking water treatment residuals, and other bioretention soil media amendments.