The development of settlement in expanded polystyrene foam (EPS) floating structure must be supported by suitable waste water infrastructure. Capacity factor analysis has been developed as a way to increase waste water technology capacity. This research purpose is to evaluate and increase biofilter capacity factor to meet requirement when a floating settlement is built in Tambak Lorok Semarang. Capacity factor identified from literature, group discussion and inspection data. The community and environment analysis conducted in Tambak Lorok settlement (n = 250). The capacity factor divided into 4 main factors to to evaluate the biofilter. Biofilter must be certified and following its service capability to fulfill the services capacity factor. Sun protector, tidal wave protector, salt water or marine resistant coating and installed only in calm wave area is needed to fulfill its technical capacity factor. Biofilter as low cost technology can fulfill the environmental economy factor needed by the community which has a low willingness to pay (Rp. 1000 / month). The evaluation and model that built in Tambak Lorok can be uses as guidelines for designing biofilter in floating Settlement or building on EPS structure.