Planning guide
WA R-Codes explained: what your R-code actually means
Your report says R20, R30 or R40. Here's where that number comes from, what it actually requires, and the common misreading that puts the wrong figure on most websites that explain it.
Written and verified by Struqt’s registered architects · Last verified October 2026
An R-code is a density code. Your council puts it on your block through its local planning scheme. But the council doesn't decide what the code means. That's set state-wide in the Residential Design Codes Volume 1, and the numbers that matter are all in one table. The most common mistake is reading the wrong column. Table D has four columns side by side: minimum site area, average site area, minimum lot area and minimum frontage. Two of those only apply to single houses.
Sources: Residential Design Codes Volume 1, Version 3 (10 April 2026) · Planning and Development Act 2005 (WA), Part 3A · Residential Design Codes, Department of Planning, Lands and Heritage
What an R-code is, and who puts it on your block
R20, R30, R40 and so on are shorthand for how intensively a block can be developed. The number is roughly how many homes per hectare the code allows for.
Two different documents do two different jobs here, and mixing them up is where most of the confusion starts:
- Your council's planning scheme decides which code applies to your block, through its zoning table and scheme maps.
- The state's Residential Design Codes decide what that code requires. They never give a code to an address; they just set the rules that follow once your council has.
So to find your code, look at your council's scheme map. To find out what it means, look at one table in the state document.
What R20, R30 and R40 require
Here's what Table D says for the three codes people ask about most. Look at the dwelling type as well as the code: the same code has different rules for a single house, a grouped dwelling and an apartment (multiple dwelling).
R20 · Single house or grouped dwelling
- Minimum site area
- 350m² per dwelling
- Average site area
- 450m² per dwelling
- Minimum lot area / rear battleaxe
- 450m² (single houses only)
- Minimum frontage
- 10m (single houses only)
R20 · Multiple dwelling
- Minimum site area
- not set
- Average site area
- 450m² per dwelling
- Minimum lot area / rear battleaxe
- not set
- Minimum frontage
- not set
R30 · Single house
- Minimum site area
- 260m² per dwelling
- Average site area
- 300m² per dwelling
- Minimum lot area / rear battleaxe
- 410m² (single houses only)
- Minimum frontage
- not set
R30 · Grouped dwelling
- Minimum site area
- 260m² per dwelling
- Average site area
- 300m² per dwelling
- Minimum lot area / rear battleaxe
- not set
- Minimum frontage
- not set
R30 · Multiple dwelling
- Minimum site area
- not set
- Average site area
- 300m² per dwelling
- Minimum lot area / rear battleaxe
- not set
- Minimum frontage
- not set
R40 · Single house
- Minimum site area
- 180m² per dwelling
- Average site area
- 220m² per dwelling
- Minimum lot area / rear battleaxe
- 380m² (single houses only)
- Minimum frontage
- not set
R40 · Grouped dwelling
- Minimum site area
- 180m² per dwelling
- Average site area
- 220m² per dwelling
- Minimum lot area / rear battleaxe
- not set
- Minimum frontage
- not set
R40 · Multiple dwelling
- Minimum site area
- not set
- Average site area
- 115m² per dwelling
- Minimum lot area / rear battleaxe
- not set
- Minimum frontage
- not set
| Code | Dwelling type | Minimum site area | Average site area | Minimum lot area / rear battleaxe | Minimum frontage |
|---|---|---|---|---|---|
| R20 | Single house or grouped dwelling | 350m² per dwelling | 450m² per dwelling | 450m² (single houses only) | 10m (single houses only) |
| R20 | Multiple dwelling | not set | 450m² per dwelling | not set | not set |
| R30 | Single house | 260m² per dwelling | 300m² per dwelling | 410m² (single houses only) | not set |
| R30 | Grouped dwelling | 260m² per dwelling | 300m² per dwelling | not set | not set |
| R30 | Multiple dwelling | not set | 300m² per dwelling | not set | not set |
| R40 | Single house | 180m² per dwelling | 220m² per dwelling | 380m² (single houses only) | not set |
| R40 | Grouped dwelling | 180m² per dwelling | 220m² per dwelling | not set | not set |
| R40 | Multiple dwelling | not set | 115m² per dwelling | not set | not set |
From Table D, Part D of the Residential Design Codes Volume 1, Version 3, read on 8 September 2026. Codes above R40 are further down the same table and aren't shown here.
Just because a split is allowed doesn’t mean it stacks up financially. That’s why our feasibility method checks the planning rules first. For how other states handle this, see minimum frontage and lot size by state.
Three ways people misread the table
- The minimum and the average are different, and you need to meet both. At R20 the minimum site area is 350m² per dwelling and the average is 450m². Clearing the minimum isn't enough. If you're building more than one home, the average across them has to work too. That's why splitting a block into two lots that both sit right on the minimum often fails.
- Two of the four columns are for single houses only. Table D marks the minimum lot area and minimum frontage columns with a symbol, and its legend says that symbol means single houses only. So the 10m frontage everyone quotes for R20 only applies to a single house. A grouped dwelling at R20 has no minimum frontage and no minimum lot area under Table D. Quoting the single-house figure for a grouped dwelling gets it wrong.
- A dash means "doesn't apply", not zero, and not unlimited. Where Table D shows a dash, that rule just isn't set for that code and dwelling type. It doesn't mean anything goes. Setbacks (how far you build from the boundary), open space, parking and your council's own scheme rules all still apply.
How frontage is measured, and what happens on odd-shaped blocks
Frontage has a specific meaning here, and it's not the width of your title boundary. The R-Codes measure it as the width of the lot at the primary street setback line (the required building setback from the street), not at the street boundary itself. If your block narrows or widens towards the street, those two numbers will be different, and the setback line one is what counts.
For battleaxe blocks (lots behind another lot, reached by a driveway) and other irregular shapes, there's no formula. Frontage is whatever the decision-maker says it is. Worth knowing before you pay for a design based on a frontage you measured yourself.
Our glossary explains minimum site area and site coverage as they appear on a report.
When a smaller lot can still be approved
There's one way to get a smaller lot through, and it's narrower than people tend to say.
The Western Australian Planning Commission, working with your council, can approve a lot (green title, survey-strata or strata) up to 5% below the minimum or average site area in Table D. It's not a general allowance you can count on. The smaller size has to help achieve one of six things:
- protecting an environmental or heritage feature
- keeping a significant part of an existing streetscape
- giving lots separate frontage to more than one street
- getting around an unusual site constraint
- allowing housing of the same type as nearby land, where the land couldn't otherwise be developed
- meeting an objective of the local planning framework.
Key takeaway: Your R-code comes from your council's scheme. What it requires comes from one state table. Before you rely on any R-code figure you've read, check three things: it's from Table D of Volume 1 (not the old Table B), it's the right row for your type of home, and you know whether it's the minimum or the average.
Frequently asked questions
What does R20 mean in Western Australia?
R20 is a density code your council puts on your block through its planning scheme. Under Table D of the Residential Design Codes Volume 1, a single house or grouped dwelling at R20 needs a minimum site area of 350m² per dwelling and an average of 450m². The table also lists a minimum lot area of 450m² and a minimum frontage of 10m, but both of those only apply to single houses.
Who decides what R-code applies to my property?
Your council, through its local planning scheme zoning table and maps. The state document sets out what each code requires, but it never gives a code to a particular block. To find your code, check your council's scheme map.
Is the R-Codes document still called State Planning Policy 7.3?
No. Clause 1.1 of the current document says it's a Planning Code made under Part 3A of the Planning and Development Act 2005, cited as Residential Design Codes Volume 1. State Planning Policy 7.3 is the old name, though plenty of websites still use it.
Can a lot smaller than the R-code minimum ever be approved?
Yes, but it's a narrow path. The Western Australian Planning Commission, working with your council, can approve a lot up to 5% below the minimum or average site area, but only if it achieves one of six listed outcomes, like protecting a heritage or environmental feature or getting around an unusual site constraint. It's the Commission's call, not something you're entitled to.
Does my R-code tell me whether I can subdivide?
It's one piece of the puzzle, not the answer. The code sets site area and, for single houses, lot area and frontage. Whether a subdivision is approved also depends on your council's scheme, any overlays or constraints on the land, access, services, and the Western Australian Planning Commission's own assessment.
Check the code on your own block
Your block's code is the one your council's scheme puts on your address. A Struqt report works through that for any Australian address, lists the rules that follow from it, and tells you clearly when a number comes from your council rather than the state.