The key point: a tiny home on footings is a granny flat
In WA the law doesn't have a separate category for "tiny homes". What matters is whether it has wheels:
- On wheels, it is treated as a caravan, under the Caravan Parks and Camping Grounds rules.
- On footings on a lot that already has a house, it is an ancillary dwelling, which is a granny flat. On an empty lot it is a single house.
So the real choice is between a granny flat (built on site or delivered as a fixed tiny home) and a tiny home on wheels.
Side by side
| Granny flat (or fixed tiny home) | Tiny home on wheels | |
|---|---|---|
| What the law calls it | Ancillary dwelling | Caravan |
| Size limit | 70 m² internal floor area to skip planning approval | Road limits: 2.5 m wide, 4.3 m high without a transport permit |
| Building permit | Yes | No (it is a vehicle), but it must be roadworthy |
| Planning approval | Not needed if it meets all the standard R-Codes rules on a residential lot | Not a planning matter; approval comes under the caravan rules |
| How long you can live in it | Permanently | Up to 5 nights with the owner's OK; up to 24 months with council approval, then re-apply |
| Can you rent it out? | Yes, to anyone | Only within what the council approval allows; permanent letting generally needs a licensed caravan park |
| Services | Connected to power, water and sewer or septic like a house | Council can require power, water, sewage and cooking facilities as approval conditions |
| Adds value to the property? | Yes, it is a permanent improvement | No, it stays a vehicle you can sell or move |
| Can you take it with you? | No | Yes |
When a granny flat is the better choice
- Someone will live in it long term, such as a parent or an adult child.
- You want rental income with no time limit on approval.
- You want to add lasting value to the property.
- Your lot fits a 70 m² flat within the standard setbacks, so you can skip planning approval.
When a tiny home on wheels is the better choice
- You need somewhere to live while you build your main house.
- The need is temporary, such as a family member staying for a year.
- You might move, and want to take the home with you.
- You can't fit a granny flat within the setbacks on your lot.
The middle option
Some people buy a tiny home on a trailer and later take the wheels off and put it on footings. At that point it becomes a dwelling and needs a building permit like any granny flat. It must meet the building code: a proper kitchen, bathroom and laundry, ceiling heights, energy efficiency, engineering and a bushfire report if the lot is bushfire-prone. Many trailer-built tiny homes need changes to pass, so check before you buy if this is the plan.