Where the water supply falls short of AS/NZS 2243.3, the need for backflow prevention has to be assessed; the guideline suggests weighing the hazards of the GMOs to be used, any cross-connections or devices that could contaminate the supply, and how likely a backflow event is. If it is needed, measures suited to the GMO risks must be put in place, and the assessment plus any measures must be documented, kept, and given to the Regulator on request. AS/NZS 3500.1 is cited for selecting and installing backflow devices.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.