Can I Subdivide a 700m² Block in Perth? New R-Code Changes Explained

A 700m² block can look like the perfect size for subdivision. Divide it into two 350m² lots, and on paper, both new lots meet the current R20 minimum. But when property owners ask the question, “Can I subdivide my 700sqm block in Perth?”, the answer is no. Under the current R-Codes, the average site area requirement of 450 m² can prevent a standard 700m² R20 block from being subdivided. A proposed WA reform could change this by removing the averaging requirement for R20 and lower-density land.

So, what does that mean for your property? This guide explains why a 700m² block currently falls short, what the proposed R-Code changes would alter, which requirements will still matter and how Perth homeowners can assess their subdivision potential.

Why Does a 700 m² Block Currently Fail to Subdivide?

According to the 2026 R20 subdivision rules, a standard 700m² R20 block currently falls short because subdivision is assessed against both a minimum lot size and an average site area requirement. Understanding the difference between these two tests explains exactly where the problem occurs.

For R20 land, the current figures are:

• Minimum lot size: 350m²
• Average site area: 450m² per dwelling
• Minimum frontage: 10m for a single house lot

That creates a simple problem for a 700sqm subdivision in WA:

• A 700m² block divided equally creates two 350m² lots.
• Each lot meets the 350m² minimum lot size for subdivision in Perth.
• But the average is still only 350m² per lot.
• The current R20 average is 450m², so the proposal does not meet the standard average requirement.
• Two lots at an average of 450m² require 900m² of total site area.

This is why it’s so important to understand the average lot size vs minimum lot size confusion. The block is not necessarily too small to physically contain two lots. It is the current average site area calculation that creates the barrier.

The proposed reform R-Code changes to subdivide blocks remove this averaging requirement for land coded R20 and below, potentially allowing an eligible 700m² R20 property to proceed using the minimum lot size test instead.

What Will Change Under the Proposed R-Code Reform?

The proposed reform is significant for smaller Perth blocks because it would remove the average lot size R20 block subdivision requirements. But it does not mean every 700m² property will automatically qualify. 

The R-Codes minimum site area table below shows how the current minimum and average requirements differ across the relevant residential codes and why a 700m² site is particularly significant at R20:

The important takeaway is that 700m² is not a new universal subdivision threshold. It is particularly relevant to R20 sites because two 350m² lots exactly use the property’s entire area. 

Therefore, the New R-code reforms are particularly important for owners of older Perth properties that have previously fallen just short of the subdivision requirements. Once you have established that your site has development potential, professionals with experience in residential construction Perth can help in planning what can be built on the resulting lots. 

Is There Already a Precedent for Smaller R20 Subdivisions?

Yes. Existing WAPC policy allows consideration of variations of more than 5% to the average lot size requirement for qualifying corner lots, provided the relevant criteria are met. It means some R20 corner blocks can have subdivision potential even though they would not meet the standard average requirement.

This existing policy is important because it shows that the proposed reform is not introducing an entirely unfamiliar approach.

Under current policy:

• Corner block subdivision can be considered for variations to the average lot size where the relevant criteria are satisfied.
• The variation is discretionary rather than an automatic entitlement.
• The WAPC still considers the site’s overall circumstances.
• Significant trees and mature vegetation can influence the required lot configuration.
• Nested or staged subdivision proposals are generally not supported simply as a way of achieving additional yield.

The proposed reform would therefore broaden the minimum-only approach rather than simply creating a completely new subdivision principle. This proposed 900sqm to 700sqm subdivision change is particularly relevant to R20 owners because removing the 450m² average requirement could allow two 350m² lots to be considered on a 700m² site. 

How Can You Check Whether Your 700m² Perth Block Could Qualify?

Block size is only the first filter. If you are asking, “Does my Perth block qualify for subdivision?”, you need to dig deeper. Before assuming your property can be subdivided, check the following characteristics because they can affect the practical outcome even when the land area appears sufficient.

• Confirm the R-Code: Check your local council’s planning maps and property information to understand 2026 Perth subdivision eligibility. R20 land is particularly relevant to the proposed reform, while R15, R17.5 and R12.5 have higher minimum lot sizes.
• Verify the title area: Use the registered land area rather than relying on a property advertisement or a rounded figure. A block described as “700m²” may not be exactly 700m². The same factors can also be useful when assessing whether your property is suitable for other forms of development, as explained in our granny flat block suitability checklist. 
• Check frontage and access: Current R20 standards include a 10m minimum frontage for single-house lots. Rear lots may also require an appropriate battleaxe arrangement.
• Look for site constraints: Easements, existing buildings, significant vegetation, heritage considerations, drainage requirements and access arrangements can influence the subdivision design. WAPC policy also notes that lot reconfiguration may be required to retain significant trees and mature vegetation.
• Check the local planning framework: Local planning schemes and policies can modify or supplement R-Code provisions, so a state-level rule should not be treated as a guaranteed approval for every Perth address.

A further practical point is servicing. Once the subdivision concept is established, design drafting and permits can form part of the next stage of turning the proposed layout into an approval-ready project. WAPC subdivision applications can be referred to councils, utilities and other agencies, and approval conditions commonly address services such as water, sewer, power and drainage.

You must also know about the costs. For a straightforward 1-into-2 lot subdivision, the subdivide block Perth cost can typically range from $40,000 – $65,000, depending on the site and requirements.

Many also ask: How many lots can I subdivide my block into Perth? The answer depends on the property’s R-Code, dimensions, frontage, access and other site-specific constraints.

Which Perth Suburbs Could Be Most Affected?

The largest opportunities are likely to occur in established residential areas containing substantial numbers of R20 lots in the 700m² to 899m² range. The State Government estimates that the proposed Residential code change in 2026 could potentially make more than 50,000 existing Perth metropolitan properties eligible for subdivision.

The City of Cockburn has identified numerous 700m²-plus corner lots in these predominantly R20 areas with existing subdivision potential under current WAPC policy. These might include the following areas:

• Bibra Lake and South Lake
• North Lake
• Coogee
• Spearwood and Lake Coogee
• Yangebup
• Leeming

If subdivision is approved and you intend to develop the new lots, working with experienced home builders Perth can be extremely beneficial for the next stage of the project. 

Is the 700m² Subdivision Rule Law Yet?

No. The change is still a proposal, so a standard 700m² R20 block does not automatically become subdividable under the new approach today. The current R-Codes continue to apply while the review is underway.

You can read our WA R-Code Reform Update 2026 for a broader explanation of the proposed changes and their potential impact on residential development in WA. 

As of September 2026:

• The R-Codes review is ongoing.
• Proposed changes are expected to be released for public consultation in late 2026.
• Implementation is anticipated from mid to late 2027, subject to consultation, endorsement and approval.
• Subdivision applications continue to be assessed under the current planning framework while the review is underway.

That distinction matters if you are considering selling, subdividing or developing your property now. The proposed reform may improve future development potential, but it should not be treated as an approval that already exists.

Conclusion

For a Perth homeowner with a 700m² R20 block, the key issue is the current averaging requirement rather than simply the amount of land available. The proposed reform could remove that barrier and open subdivision opportunities for thousands of existing properties. However, lot dimensions, frontage, access, servicing and local planning requirements will still need to be considered.

Wondering whether your specific block could work under the current rules or benefit from the proposed changes? BODA Building Group can help you assess your site’s development potential and plan the next step.

Disclaimer: Planning laws, R-Codes, government policies, local planning schemes and subdivision requirements are subject to change. The proposed R-Code reforms discussed in this article have not yet taken effect. Always confirm the current requirements with the relevant government authority or a qualified planning professional before making development decisions.