In NSW, the construction of ADUs involves a streamlined process that can be navigated easily as long as you use the services of home builders. What are the eligibility requirements for an ADU? For one thing, your property must be zoned for residential use. Secondary dwellings are permitted in Zone R1 parcels, intended for general residential development, R2 zones for low-density residential planning as well as R3, R4, and R5 lots. However, for the latter, approval will only be possible if you apply for a DA.