Western Australia · Planning guide
Subdivision rules in WA
In Western Australia you cannot subdivide, amalgamate or create a road without the approval of the Western Australian Planning Commission under section 135 of the Planning and Development Act 2005. Whether a lot can be split depends first on the density code the local planning scheme applies to it, because Part D of the R-Codes Volume 1 sets a minimum and an average site area for each code in Table D and the decision-maker cannot vary those figures except as the R-Codes or the scheme allow. Green title, survey-strata and strata lots are all measured against Table D, with defined adjustments for battleaxe access legs and corner truncations.
Sources read on 9 September 2026. Provisions are quoted word for word from the instrument.
Who approves a subdivision in WA
Subdivision in WA is a state decision, not a council one. Section 135 of the Planning and Development Act 2005 says a person is not to subdivide any lot, amalgamate lots or lay out a road without the approval of the Commission, meaning the Western Australian Planning Commission (WAPC). The local government is consulted and can recommend conditions, but the approval is issued by the WAPC.
The R-Codes are the main instrument the WAPC uses to test residential lot sizes. Part D of the Residential Design Codes Volume 1 is titled Land and its single element, clause 1.1 Site area, provides the site area requirements for all residential development, including the creation of green title, survey-strata and strata lots.
A person is not to — (a) subdivide any lot; or (b) amalgamate any lot with any other lot, whether within the same district or otherwise; or (c) lay out, grant or convey a road, without the approval of the Commission.
Read the source · retrieved 9 September 2026
Part D provides the site area requirements for all residential development. 1A To provide for a consistent and coordinated approach to residential built form and development. 1B To ensure that residential development meets community expectations in regard to appearance, use and density. 1C To promote a range of lot sizes to support housing diversity and a variety of built form typologies.
Read the source · retrieved 9 September 2026
Minimum and average site area per R-Code
Table D of the R-Codes lists, for every density code from R2 to R100-SL, a minimum site area and an average site area per dwelling, and for single houses a minimum lot area for rear battleaxe lots and a minimum frontage. The minimum applies to each lot. The average applies across all the lots in the subdivision, which is what lets one lot go down to the minimum if another is larger.
The R-Codes illustrate the pairing with their own worked figures. Figure 1.1b gives the R25 requirements as a minimum of 300m2, an average of 350m2 and a battleaxe lot of 425m2. Figure 1.1c gives R50 as a minimum of 160m2 and an average of 180m2. Every other code has its own row in Table D, and a general number cannot be quoted for WA as a whole.
The decision-maker cannot vary the Table D figures except where the R-Codes or the scheme allow. The R-Codes themselves allow a small number of variations. The WAPC, in consultation with the council, may approve a lot up to five per cent smaller than Table D where the shortfall protects an environmental or heritage feature, retains a streetscape element, gives lots frontage to more than one street, overcomes an unusual site constraint, allows housing of the same type as the surrounding area, or meets a local planning framework objective.
R25 site area requirements (min 300m2 avg 350m2, battleaxe 425m2). R50 site area requirements (min 160m2 avg 180m2, battleaxe 160m2).
Read the source · retrieved 9 September 2026
The WAPC, in consultation with the local government, may approve the creation of a green title lot, survey-strata lot or strata lot of a lesser minimum and/or average site area than that specified in Table D provided that the proposed variation would be no more than five per cent less in area than that specified in Table D and will: i. facilitate the protection of an environmental or heritage feature; ii. facilitate the retention of a significant element that contributes toward an existing streetscape worthy of retention; iii. facilitate the development of lots with separate and sufficient frontage to more than one public street; iv. overcome a special or unusual limitation on the development of the land imposed by its size, shape or other feature; v. allow land to be developed with housing of the same type and form as land in the vicinity and which would not otherwise be able to be developed; or vi. achieve specific objectives of the local planning framework.
Read the source · retrieved 9 September 2026
The decision-maker shall not vary the minimum or average site area per dwelling requirements set out in Table D except as provided for in the R-Codes Volume 1 or the scheme.
Read the source · retrieved 9 September 2026
How site area is measured: battleaxe legs and truncations
The minimum site area for a single house is the area of the green title or survey-strata lot. For a grouped dwelling it is the land the dwelling occupies plus every other area set aside for the exclusive use of that dwelling's occupants.
Clause C1.1.3 sets the adjustments. Up to 20m2 of a corner truncation to a public street is added to the adjoining lot. In areas coded R40 and below, a rear battleaxe site includes its access leg, but the leg can contribute no more than 20 per cent of the Table D site area. In areas coded R50 and above the access leg is excluded and the effective lot area must meet the minimum on its own. Where a battleaxe lot abuts a right-of-way or a reserve, half the width of that reserve up to a depth of 2m can be added.
There is also a safety valve for existing lots. Under C1.1.4, a lot approved by the WAPC, or any existing lot with permanent legal access to a public road, is accepted even if it is smaller than Table D requires.
The minimum site area set out in Table D is calculated as follows: i. in the case of a single house, the area of a green title lot or survey-strata lot; or ii. in the case of a grouped dwelling, the area of land occupied by the dwelling itself, together with all other areas whether contiguous or not, designated for the exclusive use of the occupants of that dwelling.
Read the source · retrieved 9 September 2026
in the case of a lot with a corner truncation to a public street, up to a maximum of 20m2 of that truncation shall be added to the area of the adjoining lot, survey-strata lot or strata lot as the case may be (refer Figure 1.1a); ii. in areas coded R40 and below; in the case of a rear battleaxe site, the site area is inclusive of the access leg provided that the area of the access leg contributes no more than 20 per cent of the site area as required by Table D (refer Figure 1.1b);
Read the source · retrieved 9 September 2026
iii. where the battleaxe lot (excluding the access leg) adjoins or abuts a right-of-way or reserve for open space, pedestrian access, school site or equivalent, half the width of the right-of-way or reserve (up to a maximum depth of 2m) may be added to the site area (refer Figure 1.1b and 1.1c); or iv. in areas coded R50 and above; in the case of a battleaxe lot, the vehicle and/or pedestrian access leg and associated truncations shall be excluded from the calculation of minimum site area to achieve an effective lot area consistent with the minimum site area required in Table D (refer Figure 1.1c).
Read the source · retrieved 9 September 2026
The following variations to the minimum and average site area set out in Table D may be made: i. in the case of a single house, grouped dwelling or multiple dwelling; the area of a lot, survey-strata lot or strata lot approved by the WAPC; or ii. the area of any existing lot, survey-strata lot or strata lot with permanent legal access to a public road, notwithstanding that it is less than that required in Table D.
Read the source · retrieved 9 September 2026
Strata and survey-strata of existing dwellings
Many WA subdivisions are survey-strata or strata schemes over dwellings that already exist or are being built at the same time. Part D design principle P1.1.3 lets the WAPC, in consultation with the council, approve survey-strata or strata lots for an existing authorised grouped or multiple dwelling development below the Table D minimum and average, where the development on the resulting lots is consistent with the objectives of the relevant R-Codes design elements and orderly and proper planning.
The other reductions in Part D also apply to subdivision. In areas coded R30 to R40 the minimum and average site area can be reduced by up to 35 per cent for an accessible dwelling built to gold level universal design or a small dwelling, provided no single house or grouped dwelling site is under 100m2 and, in a subdivision of four or more sites, no more than half the sites use the reduction.
The WAPC, in consultation with the local government, may approve the creation of a survey-strata lot or strata lot for an existing authorised grouped dwelling or multiple dwelling development of a lesser minimum and average site area than that specified in Table D, where, in the opinion of the WAPC or the local government, the development on the resulting survey-strata or strata lots is consistent with the objectives of the relevant design elements of the R-Codes, and the orderly and proper planning of the locality.
Read the source · retrieved 9 September 2026
In areas coded R30 to R40; for an accessible dwelling designed to gold level universal design (in accordance with Part B, 5.5.4 C4 or Part C, C2.7.2), or a small dwelling (in accordance with Part B, 5.5.5 C5 or Part C, C2.9.1) that is the subject of a development proposal, the minimum and average site area of Table D may be reduced by up to 35 per cent, provided that: i. for single houses and grouped dwellings, no site is less than 100m2; and ii. for development or subdivision of 4 or more dwellings or sites, the site area reduction is limited to a maximum 50 per cent of the total number of dwellings or sites.
Read the source · retrieved 9 September 2026
Works to carry out an approved subdivision
Subdivision approval and development approval are separate. Once the WAPC has approved a plan of subdivision, the deemed provisions note that section 157 of the Act applies to the works needed to carry it out, and the WAPC's own subdivision conditions cover matters such as services and road works. Building a new house on the new lot is then a separate question answered by the clause 61 exemption or a development application, followed by a building permit.
Section 157 of the Act applies in respect of the carrying out of works necessary to enable the subdivision of land if the Commission has approved a plan of the subdivision.
Read the source · retrieved 9 September 2026
What changes council by council in Western Australia
The state instruments set the frame. These points are set by each council's own instrument or mapping, so the answer for an address depends on which council it sits in.
- The density code on the lot, set by the local planning scheme map, picks the Table D row that applies. Split codes and dual codes in a scheme can make the higher code conditional on scheme criteria.
- A scheme can amend, replace, augment or exclude R-Codes provisions as the Regulations allow, so a scheme may impose its own minimum lot size or frontage on top of Table D.
- Local planning frameworks can add objectives that the WAPC may rely on when approving a lot up to five per cent below Table D under P1.1.2(vi).
- Structure plans, precinct structure plans and local development plans can amend or replace deemed-to-comply provisions, and the WAPC consults the local government on every subdivision application.
- Council-specific conditions on services, road widening and public open space contributions come through the WAPC approval and vary by district.
For your address
How the $150 report settles this for one site
A Casa preliminary planning report reads the density code at your parcel from the local planning scheme, applies the Table D minimum and average site area for that code, and runs the C1.1.3 adjustments for any battleaxe leg, truncation or abutting reserve to show how many lots the land supports on the deemed-to-comply numbers. It flags mapped overlays and scheme clauses that change the outcome. The WAPC decision and its conditions remain a separate step.
Common questions
Who approves subdivision in WA, the council or the state?
The Western Australian Planning Commission. Section 135 of the Planning and Development Act 2005 says a person is not to subdivide any lot without the approval of the Commission. The local government is consulted but does not issue the approval.
What is the minimum lot size for subdivision in WA?
There is no statewide number. Table D of the R-Codes sets a minimum and an average site area for each density code, and your lot's code comes from the local planning scheme. The R-Codes' own figures show R25 as a minimum of 300m2 and an average of 350m2, and R50 as a minimum of 160m2 and an average of 180m2, but you must read the row for your code.
Can I subdivide if I am just under the minimum?
Only through the routes the R-Codes allow. Design principle P1.1.2 lets the WAPC, in consultation with the council, approve a lot up to five per cent smaller than Table D where one of six listed reasons applies. Otherwise the decision-maker cannot vary the Table D figure.
Does the driveway of a battleaxe lot count toward the site area?
In areas coded R40 and below the access leg counts, capped at 20 per cent of the Table D site area. In areas coded R50 and above the access leg is excluded and the effective lot area behind it must meet the minimum on its own.
Can I strata title an existing pair of units that are under the site area?
Possibly. Design principle P1.1.3 lets the WAPC, in consultation with the council, approve survey-strata or strata lots for an existing authorised grouped or multiple dwelling development below the Table D figures where the development on the resulting lots is consistent with the R-Codes objectives and orderly and proper planning.
Sources read for this guide
- Planning and Development Act 2005 (WA), official version as at 19 Feb 2026read 9 September 2026
- Residential Design Codes Volume 1 (R-Codes Volume 1), Version 3 published 10 April 2026, Western Australian Planning Commissionread 9 September 2026
- Planning and Development (Local Planning Schemes) Regulations 2015 (WA), official version as at 03 Nov 2024read 9 September 2026
Not covered here
- Table D rows are a multi-column table that does not extract as verbatim sentences, so this guide quotes the R-Codes' figure captions for R25 and R50 and describes the table's structure rather than reproducing every row.
- Section 157 of the Planning and Development Act 2005 (works to carry out an approved subdivision) was not fetched in full and is referenced only through the note in clause 61 of the deemed provisions.
- WAPC subdivision policies and the standard conditions applied to subdivision approvals were not fetched and are not described.
- R-Codes Volume 1 quotes were taken from Casa's cached copy of the wa.gov.au PDF (sha256 18dfd0c7, fetched 2026-09-08 and re-read 2026-09-09). The Act and Regulations were fetched live from legislation.wa.gov.au on 2026-09-09.
More WA guides
- Granny flat rules in WA
- Dual occupancy rules in WA
- Fast-track approvals in WA
- Height and setback rules in WA
- Do I need a DA in WA?
Subdivision and minimum lot size rules in other states
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