This online case study provides an extensive review of the Omega Center building, site, processes, and systems. The Omega Center for Sustainable Living (OCSL) is a purposeful building and site, designed to clean water, return the clean water to the local systems, and educate users about the process. The design team selected engineered biological wastewater treatment system technologies to clean the water using the earth, plants and sunlight. The entire building and water process use site-harvested renewable energy achieving a net-zero energy system. To achieve this goal the facility had to be free of waste (volume, material, energy), organized, and carefully tuned to harvest solar energy for passive heating and lighting, using the entire mass for thermal comfort. The resultant design's simplicity and elegance suits its purpose well.