A granny flat in Western Australia is legally an “ancillary dwelling”, and the rules for getting one approved changed for the better in April 2024. If your design meets the R-Codes, you no longer need planning approval, only a building permit. This guide covers what changed, the conditions your build must meet, and how approval works.
Key Takeaways
- Since 10 April 2024, R-code compliant granny flats up to 70sqm need no planning approval on residential lots of any size in WA (WA Government).
- A building permit is still required for every granny flat, even when planning approval is not.
- The old 350sqm minimum lot size was removed, so many more Perth blocks now qualify.
- Your build must still meet setbacks, the 70sqm floor area cap and other deemed-to-comply standards.
Do You Need Council Approval for a Granny Flat in WA?
In most cases, no. Since 10 April 2024, a granny flat that complies with the Residential Design Codes (the R-Codes) does not need planning approval anywhere in WA, on a lot of any size. You still apply for a building permit, but the planning approval step is removed for compliant builds.
Before the reform, an ancillary dwelling generally needed a lot of at least 350sqm, and often planning approval on top. That minimum lot size is gone. The logic is simple: meet the standards, and you skip planning approval; miss them, and you lodge a planning application.
“Since 10 April 2024, a compliant granny flat (ancillary dwelling) in WA that does not exceed 70sqm no longer requires planning approval, on a residential lot of any size. A building permit from the local council is still required.”
Planning Approval vs a Building Permit: What’s the Difference?
Planning approval and a building permit are two separate things, and the 2024 reform only removed the first for compliant granny flats. The table below shows what each one checks, and you will always need the permit.
| Step | What it checks | Needed for a compliant granny flat? |
| Planning approval | Land use, setbacks, streetscape, local scheme | No, if R-code compliant |
| Building permit | Structure, safety, energy, building standards | Yes, always |
What Conditions Must Your Granny Flat Meet?
To skip planning approval, your granny flat has to satisfy the R-Codes deemed-to-comply standards. The headline rule is a maximum internal floor area of 70sqm. It must also sit on the same lot as a house and meet your local setback rules.
| Requirement | The standard |
| Maximum floor area | 70sqm internal |
| Lot size | No minimum since April 2024 |
| Setbacks | As set by your local planning scheme |
| Parking | Usually none required (some exceptions) |
| Design match | No longer needs to match the main house |
“For a WA granny flat to avoid planning approval, it must meet the R-Codes deemed-to-comply standards: a maximum internal floor area of 70sqm, compliant local setbacks, and placement on the same lot as a single house.”
How Do You Get a Building Permit in WA?
Once your design is compliant, getting a building permit is a paperwork process through your local council. A registered builder usually prepares and lodges the application for you. Here is the typical path from plan to permit.
- Finalise your granny flat design and confirm it meets the R-Codes.
- Prepare the working drawings, engineering and required documentation.
- Lodge the building permit application with your local government.
- Pay the permit and application fees.
- Receive your permit, then construction can begin.
Timelines vary by council, but removing the planning step usually saves several weeks. WA building standards are overseen by the Building and Energy division.
When Do You Still Need Planning Approval?
The exemption is not universal. If your granny flat breaks a deemed-to-comply rule, or your site carries extra planning controls, you will still need planning approval. Check these before you lock in a design.
- A floor area over 70sqm.
- Heritage-listed properties or designated heritage areas.
- Special control areas, or bushfire and flood-prone land.
- Designs that do not meet setback or other R-Code standards.
- Some strata and survey-strata arrangements.
How does Classic WA handle Approvals for You?
Approvals are where a lot of granny flat projects stall. Classic WA runs a turn-key process, so the drafting, documentation and building permit are handled in-house. With 75 years of combined experience and builder registration BC12890, the team knows what each Perth council expects. You can browse the Classic WA granny flat range to find a compliant design, or a two-bedroom layout that stays within the 70sqm cap.
Frequently Asked Questions
Do I need council approval for a granny flat in WA?
For most compliant builds, no. Since April 2024, a granny flat up to 70sqm that meets the R-Codes needs no planning approval on a residential lot of any size. You do still need a building permit.
What is the maximum size of a granny flat in WA?
The maximum internal floor area for an ancillary dwelling in WA is 70sqm. Staying at or under this size is one of the key conditions for avoiding planning approval.
Is there a minimum lot size for a granny flat in WA?
No. The previous 350sqm minimum lot size was removed on 10 April 2024. A compliant granny flat can now be built on a residential lot of any size.
How long does granny flat approval take in WA?
Because compliant builds skip planning approval, the main step is the building permit. Timelines vary by council, but that usually saves several weeks. A turn-key builder can lodge the paperwork for you.
Check Your Block Against the Rules
Granny flat approvals in WA are simpler than they used to be, but the details still matter. If you would like your block checked against the current rules, Classic WA can talk you through it. Get in touch with the team, or explore finance options if you are weighing up the numbers. Our showrooms are at Joondalup (37 Winton Road) and Canning Vale (5 South Street).