The 2027 WA R-Codes Reform Explained: What Was Actually Announced

On 2 July 2026 the WA Government announced the biggest change to the Residential Design Codes in three decades: a proposal to abolish the average site area rule for blocks coded R20 and below. If it proceeds as announced, roughly 50,000 Perth blocks that cannot be subdivided today would become subdividable.

Here is what was actually announced, in plain English, and what it would mean for your block.

The rule that would disappear

Every R-Code carries two numbers that decide how many dwellings a block supports: a minimum site area per dwelling, and an average. At R20, the minimum is 350 sqm and the average is 450 sqm, and the average is the one that bites. An 855 sqm R20 block clears two lots on the minimum (700 sqm needed) but fails the average (900 sqm needed), so today it stays a single-home block.

The announced reform proposes removing the average for R20 and below entirely, leaving the minimum to govern. That same 855 sqm block would support two dwellings.

Who it affects, and who it does not

The proposal as announced applies to R20 and below, which covers most of suburban Perth’s traditional quarter-acre belt. Blocks coded R25 and above are not affected by this change as announced: their averages remain.

Whether your specific block flips depends on one piece of arithmetic: is your lot area at least twice the minimum for your code, but less than twice the average? For R20, that window is 700 to 899 sqm, which is an enormous share of older Perth suburbs.

The honest caveats

This is a proposal, not law. Consultation is expected in late 2026, gazettal is targeted for mid-2027, and the detail can change between announcement and gazettal, as it did with the medium density code between 2023 and 2024. Nobody should buy, sell or knock anything down on the strength of an announcement.

There is also more to subdivision than the density arithmetic: sewer position, easements on the title, frontage, verge infrastructure and your council’s local planning policies all still apply, reform or no reform.

What to do now

If you own a block in the affected window, the sensible move is to know your numbers before the market prices them in. Check what your block supports under today’s rules and what the announced reform would change: our free R-Code check shows both side by side, clearly labelled, with the proposal never counted in the headline result. Then, if the answer matters to your plans, get the verification work done early: title, sewer, comparables, so you can move on facts when the consultation lands.

Frequently asked questions

Is the R-Codes reform law yet? No. It was announced on 2 July 2026, consultation is expected late 2026, and gazettal is targeted for mid-2027. It may change.

Which blocks are affected? As announced, blocks coded R20 and below whose lot area clears a multiple of the minimum site area but not the average. For R20 that is roughly the 700 to 899 sqm window for a two-lot outcome.

Does this change R30 or R40 blocks? No. The announced change applies to R20 and below only.

Should I wait for the reform before developing? It depends on your block and your goals. If your block already supports development under current rules, waiting carries its own costs. If your block only works under the reform, the decision is about timing and risk. That trade-off is exactly what a feasibility resolves.