Costs, size limits, block size, setbacks, renting and tax, with the numbers and the government source for each. Checked October 2026.
About $176,000 to $255,000 for a 60 m² two-bedroom granny flat built by a builder, all-in. That covers the building, design, building permit, connections and basic landscaping, including GST, on a flat block with services nearby. Roughly $3,600 per m². A slope, a sewer pump or tight access adds $10,000 to $50,000 or more. Work out your own.
About $194,000 to $285,000 for a 60 m² two-bedroom granny flat, all-in, or roughly $4,000 per m². Sydney costs more than other capitals mainly because of labour, and rock or sandstone excavation on some blocks. Work out your own.
About $158,000 to $231,000 for a 60 m² two-bedroom granny flat, all-in, or roughly $3,200 per m². In Brisbane, council infrastructure charges can add around $10,000 to $22,000 if the flat is over 50 m². Work out your own.
About $158,000 to $237,000 for a 60 m² two-bedroom granny flat, all-in, or roughly $3,300 per m². Water and sewer connections in Perth often run $7,500 to $19,000 on their own. Work out your own.
Usually everything outside the building: design, the building permit and surveyor or certifier, the soil test, water, sewer and power connections, and putting the yard back. On an easy block that adds about $20,000 to $50,000. Ask any builder for a written list of what is excluded. See the full breakdown.
60 m² of floor area or less. Victoria calls it a small second dwelling. It must be on the same lot as an existing house, only one is allowed per lot, and it needs its own kitchen, bathroom and toilet. Source: Planning Victoria.
Usually not. In residential zones there is no planning permit if the lot is 300 m² or more and the flat is 60 m² or less. Heritage and some other overlays can still be fine if the flat is under 5 m high with muted colours. Bushfire and flood areas need a permit. You always need a building permit. Source: Planning Victoria. Check your block’s zone and overlays.
300 m² for the no-permit pathway in a residential zone. Below 300 m² you can still apply, but you will need a planning permit. A garden area requirement also applies, so a bigger house on a small lot can leave no room. Source: Planning Victoria. See what fits on your lot in 3D.
It follows the normal siting rules for a house. As a guide, walls up to 3.6 m high sit at least 1 m from the side and rear boundaries, plus 0.3 m for every metre higher. Some walls can go on the boundary within length and height limits. Your building surveyor confirms the exact numbers. Source: Building and Plumbing Commission, practice note SI-03.
No. A small second dwelling must not be connected to reticulated natural gas, so plan for an all-electric kitchen, hot water and heating. Source: Planning Victoria.
Not in Victoria or NSW. A small second dwelling in Victoria cannot be subdivided from the main house, and in NSW the lot with a secondary dwelling cannot be subdivided. It is sold with the property. Sources: Planning Victoria, NSW Planning.
450 m² for fast-track approval through a Complying Development Certificate. The granny flat can be up to 60 m², and the lot cannot be subdivided. Under complying development, side setbacks are typically 0.9 m and the rear setback 3 m. Smaller lots can still go through a council development application. Source: NSW Planning.
Yes, to anyone, since 26 September 2022. Before that, Queensland granny flats were mostly limited to family. A new one needs building approval, and your council sets the size and may need a development application. Source: Queensland Government.
Not if it is 70 m² or less, on residential land and meets the R-Codes, since 10 April 2024. You still need a building permit. The old 350 m² minimum lot size was removed, and most sites need no extra parking bay. Source: WA Government.
Yes. Anyone can live in a small second dwelling or rent it, family or not. Normal rental minimum standards apply, including smoke alarms. Source: Planning Victoria. Work out the rental return.
Usually less than a unit. Melbourne’s median asking rent for units was $600 a week in June 2026 (Domain). Granny flats share a block and are smaller, so in the listings we checked a two-bedroom granny flat typically rents for about $450 to $550 a week, and a studio or one-bedroom for about $300 to $400. Work out the yield.
It can. If you rent it out at market rent, the part of your property used to earn rent can lose some of the main residence exemption. A separate exemption has applied since 1 July 2021 for a non-commercial granny flat arrangement, for example an older parent who has a written right to live there for life. Talk to your accountant. Source: Australian Taxation Office.
Usually not. Victoria requires no car parking for a small second dwelling, NSW requires no extra parking for a secondary dwelling, and WA has dropped the parking bay in most places. Sources: Planning Victoria, NSW Planning, WA Government.
General information only, not legal, tax or planning advice. Rules change, so confirm with your council, building surveyor or certifier before you build.