This Australian Technical Specification sets out requirements for manual or automated changeover devices of nominal sizes DN20/25 and maximum allowable operating pressures up to and including 1600kPa, which enable the interconnection from a pressurized rainwater tank supply and a water service to designated fixtures and outlets.Rainwater/mains supply changeover devices are intended to be used in properties that have both rainwater and mains water supply, to enable either water supply to be directed to certain fixtures and outlets, where permitted by the authority having jurisdiction.