Phosphorus presents a unique challenge to watershed managers where residences are served by onsite septic systems due to dearth of available treatment technologies and the role that phosphorus plays in the eutrophication of many freshwater ecosystems. Three efforts were conducted to summarize the state of the art regarding phosphorus management from onsite septic systems and make recommendations for further research. Foremost, an open solicitation resulted in the testing of three technologies that attempt to remove phosphorus. Tests were conducted at the Massachusetts Alternative Septic System Test Center in Massachusetts (MASSTC) during 2002 – 2003. Secondly, data collected at that facility since 1999 from standard septic tank-soil absorption systems and various advanced treatment units were used to gain a better understanding of factors that promote phosphorus reduction. These analyses also allowed the formation of recommendations to standard septic system designs to enhance phosphorus removal. Finally, a literature review regarding technologies not directly tested as well as alternative approaches to phosphorus management was conducted. These efforts were coincident with a project of the National Decentralized Resources Capacity Development Project (Etnier et al. 2005) that was charged with the evaluation of phosphorus management in the micro-scale, and the reader is encouraged to also read this document, since the technologies reported on herein are placed in evaluation matrices comparing them with various other phosphorus management strategies.