Granny Flats rules in Western Australia (2026)
Yes. An ancillary dwelling of up to 70 m² that meets the R-Codes deemed-to-comply rules needs no planning approval - just a building permit - and there has been no minimum lot size since April 2024.
No planning approval if it meets the R-Codes
Yes. An ancillary dwelling of up to 70 m² that meets the R-Codes deemed-to-comply rules needs no planning approval - just a building permit - and there has been no minimum lot size since April 2024.
Key rules at a glance
| Maximum floor area | 70 m² (deemed-to-comply) |
| Minimum lot size | None (350 m² minimum removed April 2024) |
| Planning approval | Not required if deemed-to-comply |
| Setbacks | Per the local planning scheme |
| Can it be rented? | Yes - separately from the main house |
| Self-contained | Yes (own kitchen and bathroom) |
Conditions & eligibility
- Must be on the same lot as a single house (the main dwelling).
- Deemed-to-comply floor area limit is 70 m².
- No minimum lot size since April 2024.
- Can be rented out separately from the main house.
- Must meet the setback and open space rules of the local planning scheme.
Heritage, flood and bushfire controls on your specific lot can remove the fast-track and require a full application — even when the general rules say you're fine.
How approval works in Western Australia
If the ancillary dwelling meets the Residential Design Codes (R-Codes) deemed-to-comply standards - 70 m² and the required setbacks - no planning approval is needed and you go straight to a building permit. Otherwise you apply to the local government for development approval.
Local governments set the applicable setback and R-Code density requirements, and can require development approval where the deemed-to-comply standards are not met.
Granny Flats rules by council in Western Australia
Local councils apply the Western Australia framework and can add their own controls. Pick your council:
Frequently asked questions
Do I need planning approval for a granny flat in WA?
Not if it meets the deemed-to-comply rules of the R-Codes - up to 70 m² and the required setbacks - in which case only a building permit is needed.
How big can an ancillary dwelling be in WA?
Up to 70 m² of floor area to qualify as deemed-to-comply under the Residential Design Codes.
Can I rent out an ancillary dwelling in Western Australia?
Yes. Since 2020 an ancillary dwelling can be rented out separately from the main house, and since April 2024 there is no minimum lot size.
Sources
- Ancillary dwelling (granny flat) information sheet - WA Planning ↗
- Revised R-Codes now in effect - WA Planning ↗
Related building rules
This is general guidance, not professional planning advice. Figures are summarised from the sources above and can change — confirm with your council or the WA Planning before starting work. Last reviewed: July 2026.
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