State Environmental Planning Policy (Exempt and Complying Development Codes) 2008
3A.25 Principal private open space
(1) A lot in Zone R5 that has an area of less than 4,000m2 and on which a new dwelling house is erected must have at least 24m2 of principal private open space.
(2) In this clause, principal private open space means an area that:
(a) is directly accessible from, and adjacent to, a habitable room, other than a bedroom, and
(b) is at least 3m wide, and
(c) is not steeper than 1:50 gradient.