Granny Flats & Secondary Dwellings Under the Housing SEPP

Secondary dwellings — granny flats — became one of NSW's most popular projects after state policy enabled them as complying development. Under the Housing SEPP, a secondary dwelling can often be approved by a private certifier in weeks, not months.

The headline requirements: your lot must generally be at least 450m², in a zone where secondary dwellings are permissible, with the dwelling capped at 60m² floor area (larger in some rural zones), and meeting boundary setbacks, site coverage and landscaping standards.

Only one secondary dwelling is permitted per lot, and the land generally cannot be subdivided to separate it (except in specific low-rise housing reform scenarios). It shares the title of the principal dwelling.

The traps are site-specific: corner lot setbacks, battle-axe blocks, bushfire-prone land, flood controls and heritage areas can each alter or block the complying pathway. Verify before you order plans.

Done right, a secondary dwelling adds genuine value and flexibility. Done blind, it becomes an expensive lesson. The difference is a structured site investigation — which is precisely what our toolkits are built for.