Western Australia has released its draft Residential Design Codes for public comment. Bigger granny flats, lighter parking rules and subdivision across more than 70,000 Perth and Peel blocks are on the table until 26 February 2027.
WA has proposed bigger granny flats with no extra parking
Western Australia’s rules for backyard granny flats are set to become more generous, if the draft survives consultation.
The Western Australian Planning Commission (WAPC) released its draft Residential Design Codes on 24 October 2026. Submissions close at 5pm AWST on Friday 26 February 2027.
The codes, known in WA as the R Codes, control lot sizes, heights, parking, setbacks, open space, privacy and landscaping for housing across the state.
For granny flats, which the codes call ancillary dwellings, the Table of Changes and Information Sheet 3 set out three main shifts.
The maximum internal floor area rises from 70 to 90 square metres. No additional car bay is required for the granny flat in Perth and Peel. And local governments could allow granny flats larger than 90 square metres through their own local planning policies, without separate WAPC approval.
Rear lot boundary setbacks would also come down for lots coded R5 to R15, a change that applies to granny flats and houses alike.
The 90 square metre limit applies only where every standard is met
Since April 2024, a WA granny flat that meets the codes’ standard provisions has not needed planning approval. Owners go straight to a building permit. The constraint has been the 70 square metre cap.
In our reading, the extra 20 square metres widens what can be offered inside that pathway, including two bedroom layouts that are hard to fit under 70.
A bigger granny flat only stays outside the planning system if the whole lot still works.
Under the draft, a 90 square metre granny flat still needs a building permit. It skips planning approval only where it meets every relevant “deemed exempt” provision. That is the draft’s new name for what are currently called deemed to comply standards.
Those standards are not assessed on the granny flat alone. Site cover, lot boundary setbacks and solar access for neighbours are assessed together with the main house.
The granny flat also cannot stop the main house meeting its own site cover, private open space, soft landscaping, tree and deep soil requirements. That matters more under the draft, which proposes 15 per cent soft landscaping on every site and minimum tree planting for houses.
A bigger granny flat only stays outside the planning system if the whole lot still works.
Two limits stay in place. The 70 square metre cap still applies where a granny flat shares a site with a small dwelling. The small dwelling limit itself also stays at 70 square metres, which the WAPC says is intentional. And outside Perth and Peel, the Table of Changes keeps a parking requirement for granny flats under new regional parking settings.
What is a deemed exempt granny flat in WA?
Under the draft Residential Design Codes, a deemed exempt granny flat is an ancillary dwelling of up to 90 square metres of internal floor area, one per site, that meets every applicable deemed exempt provision for size, parking, site cover, height, setbacks and related elements. Where all of those provisions are met, the development may be exempt from planning approval and proceeds with a building permit. The 70 square metre limit applies where the site also holds a small dwelling. If any provision is not met, the proposal is assessed against merit criteria by the local government.
The lot size reform grew between July and October
We covered the July announcement when the State Government first flagged the overhaul.
At that point, the July media statement proposed abolishing the average lot size rule for land coded R20 and below. It said more than 50,000 existing Perth properties could become eligible to subdivide.
The draft goes further. It proposes removing average site area requirements for land coded R10 to R25 in the Perth and Peel regions. The government now puts the number of newly eligible properties at more than 70,000.
Minimum site area requirements would stay. The review is also exploring a reduction of up to 10 per cent in minimum site area where an existing house is retained. It would also let local governments consider variations of up to 5 per cent to site area requirements through development approval.
There is an important qualifier. The lot size information sheet describes this part of the review as still under investigation. It asks whether average site area should be removed at all, and whether the code range is right.
The pressure behind the change is infill. The same information sheet says about 47 per cent of future housing in Perth and Peel is planned to come from infill in established areas, and that infill is not being delivered at the levels anticipated. The July statement put Perth’s annual infill rate at 39 per cent in 2024, up from 34 per cent in 2023.
The draft also changes heights, setbacks and parking for houses
For lower density housing, the draft simplifies a set of provisions builders deal with on most jobs.
R40 coded lots would allow three storeys, up from two. Lot boundary setbacks would be based on wall height alone. For an R20 house, that means 1 metre for one storey and 1.5 metres for two.
Site cover would replace open space as the measure for lower density codes, with no site cover limit at all for R30 and above. Visual privacy setbacks would shrink, with the cone of vision to a bedroom dropping from 4.5 metres to 3 metres.
Parking minimums would fall for single houses coded R40 and below. In Perth and Peel, homes with one or two bedrooms would need no car bay if they sit near a train station or high frequency bus route, or inside an activity centre.
Apartments move to Low, Mid and High Rise codes
The current apartment coding system would be replaced with Low Rise, Mid Rise and High Rise codes.
According to the apartments information sheet, a new Mid Rise code would support up to 6 storeys. Two new High Rise codes would support up to 16 and 20 storeys. Existing settings also rise. The current 9 storey apartment code would move to 12 storeys, and the current 6 storey code to 8.
Resident parking minimums would be removed for all apartment developments. The new Mid Rise and High Rise codes would only be applied through future local planning scheme amendments. The higher limits for existing codes would apply wherever those codes are already in place.
WA would sit at the top end on granny flat size
Granny flat size limits differ across the country, and several states have moved in the past two years.
| State | Granny flat size setting | Status |
|---|---|---|
| Western Australia | 70 square metres, proposed to rise to 90 | Draft, consultation to 26 February 2027 |
| Victoria | 80 square metres, up from 60 | In effect from 15 October 2026 |
| Tasmania | 60 square metres, proposed to rise to 90 | Draft amendment, exhibited June to July 2026 |
| South Australia | 70 square metres, up from 60 | In effect, November 2024 |
| New South Wales | 60 square metres in residential zones | Current, under the Housing SEPP |
| Queensland | Size not changed by the 2022 reform | Renting to people outside the household allowed since September 2022 |
Sources: Planning Victoria, Tasmanian State Planning Office, SA Department for Housing and Urban Development, NSW Housing SEPP, Queensland Residential Tenancies Authority.
For builders, these are proposals and the current rules still apply
None of this is law yet. The July statement said implementation is expected from mid 2027. The October statement says feedback will shape the final codes before they go to the WAPC for consideration.
Until then, granny flats in WA remain capped at 70 square metres for the exempt pathway. Anything larger, or anything that misses a standard, goes through planning approval.
The WAPC says the granny flat changes are being tested on how well they work, not whether they should proceed. The lot size changes are more open, with the department seeking views on whether they go ahead at all.
The WAPC is running five in person community sessions across Perth between 2 and 10 December 2026, plus an online drop in session on 8 December. Submissions can be lodged through the online feedback forms or posted to the WAPC.
The Good Builder Take
The granny flat changes look settled in direction. The subdivision numbers do not. The 70,000 figure rests on a reform the department itself says is still being tested. For builders pricing infill and secondary dwelling work in Perth and Peel, the granny flat rules are the firmer ground to plan around, and the consultation is where the subdivision detail will be decided.
We will follow the final codes when the WAPC releases them. Join our community and listen to The Good Builder Podcast for more on what housing policy changes mean on site.
Frequently asked questions
Under the current Residential Design Codes, a granny flat that meets all standard provisions can be up to 70 square metres without planning approval. The draft codes released on 24 October 2026 propose lifting this to 90 square metres. A building permit is still required in both cases.
Under the draft, no additional car bay would be required for a granny flat in the Perth and Peel regions. Outside Perth and Peel, the draft keeps a parking requirement for granny flats under new regional parking settings.
They are not in effect. Consultation closes at 5pm AWST on 26 February 2027. The WAPC will then consider a final version, and the State Government has said implementation is expected from mid 2027.
The State Government says removing average lot size requirements for land coded R10 to R25 in Perth and Peel would make more than 70,000 existing properties eligible to subdivide. The department is still seeking feedback on whether that change should proceed.
At 90 square metres, WA’s proposal would match Tasmania’s draft and sit above Victoria’s 80 square metres, South Australia’s 70 square metres and the 60 square metres that applies in NSW residential zones.
Related articles
- WA Moves to Let 50,000 Perth Blocks Subdivide in the Biggest R-Codes Overhaul in Three Decades
- Australian Construction Industry Trends Guide
Last updated: 26 October 2026. Figures reflect the WAPC draft R-Codes consultation documents dated 24 October 2026.
General Information Only: This article provides general information only and does not constitute legal, financial, planning or professional advice. The proposed changes described are drafts under public consultation and may change before any final codes are adopted. Readers should seek advice specific to their circumstances and check current requirements with their local government before acting.
Author: TGB Editorial
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