Insights · 8 July 2026
What R-Codes Really Mean: R20, R40, R60 Explained Clearly
R-Codes decide what can be built on every WA block. What R20, R40 and R60 actually mean, how density works, and why the code on your block matters.
Every residential block in Western Australia carries an R-Code, and that code, more than the suburb, the street or the view, decides what the land can legally become. If you own property in Perth or you’re thinking about buying for development, the R-Code is the first thing worth understanding.
Here’s what the numbers actually mean, without the planning jargon.
What an R-Code is
R-Codes come from the Residential Design Codes of Western Australia, the state planning framework that governs residential development. The “R” stands for residential, and the number describes density: roughly, how many dwellings are contemplated per hectare of land.
- R20 ≈ 20 dwellings per hectare
- R40 ≈ 40 dwellings per hectare
- R60 ≈ 60 dwellings per hectare
Nobody develops a whole hectare at a time in the suburbs, so the practical translation is minimum site area per dwelling: how much land each dwelling needs under that code.
The numbers that matter
As a working guide under the R-Codes:
| Code | Average site area per dwelling | What it typically means |
|---|---|---|
| R20 | ~450 sqm | Standard single-house suburbia; a 900+ sqm block may support two dwellings |
| R30 | ~300 sqm | Duplex and triplex territory on ordinary blocks |
| R40 | ~220 sqm | Multi-unit sites; a 700 sqm block starts working hard |
| R60 | ~150 sqm | Higher-density infill: grouped dwellings, small apartments |
Treat these as orientation, not gospel. The R-Codes distinguish between average and minimum site areas, and local planning schemes can vary requirements. But the pattern is the point: the higher the number, the more dwellings the same land can carry.
Why the same block can be worth very different money
Two identical 800 sqm blocks on the same street: one zoned R20, one zoned R40. The R20 block is a house on a big backyard. The R40 block is potentially three dwellings, which means its value is anchored to what a developer can build, not just what a family will pay to live there.
This is why rezoning quietly rewrites suburb economics, and why “my neighbour subdivided” doesn’t mean you can: the code, the lot dimensions and the services do the deciding. It’s also why the first step in working out whether your block can be subdivided is always checking the code.
Split codes: R20/R40 and friends
Across Perth you’ll see dual codings like R20/R40 or R20/R60. These mean the base density is the first number, but the higher density becomes available if specified conditions are met, commonly lot size thresholds, location criteria or design requirements set by the local scheme.
Split codes are where a lot of hidden potential lives, because owners read the first number and stop. If your block carries a split code, the conditions attached to the higher code are worth understanding in detail before you write the land off, or bank on it.
What R-Codes don’t tell you
A favourable R-Code is necessary but nowhere near sufficient. The code says nothing about:
- Lot shape and frontage. Density means little if the block can’t physically fit compliant dwellings, setbacks and access.
- Services. Sewer, power and water capacity can make or break a subdivision budget.
- Site conditions. Slope, retained fill, trees and easements all cost money.
- Feasibility. The block might legally support three dwellings that lose money to build.
The R-Code opens the door; the numbers decide whether it’s worth walking through. That’s a feasibility question, and it’s exactly the discipline in our Perth Development Feasibility Checklist.
How to check your block’s R-Code
Your local council’s planning scheme maps show the coding for every lot, and most WA councils publish them online. Between the code, your lot size and your street frontage, a competent advisor can tell you in one conversation whether your block deserves a proper assessment and, just as importantly, whether it doesn’t.
Own a block and wondering what it could carry? That’s precisely what our R-Code and feasibility assessment answers, honestly and before you spend serious money. Book a 45-minute consultation and bring your address.