This note includes descriptions of the different systems used for the on-site treatment and disposal/reuse of domestic wastewaters from residential developments in non-sewered areas in Australia. It also examines greywater treatment and reuse, which may be relevant in sewered areas. A number of well-known and emerging small-scale options are discussed, as well as the site and soil assessment requirements and land capability considerations which are required in the process of selecting and sizing an appropriate system. Aspects of the design, performance, and maintenance requirements of each of the systems are also described in this note.