Dual occupancy rules in the ACT

The E01 Residential Zones Policy applies to all development in RZ1 to RZ5, and its Land Use Table marks multi-unit housing with a Y in every one of those zones. The table's preamble says listed uses require development approval unless they are exempt under the Planning Act, and uses not listed are prohibited. Multi-unit housing is therefore a permitted, assessable use across the residential zones.

Exempt status is never available for a second dwelling. Criterion 5 in Schedule 1 of the Planning (Exempt Development) Regulation 2023 says development must not increase the number of dwellings on a block to 2 or more dwellings. A dual occupancy does that by definition, so it is always a development application to the Territory Planning Authority under section 166 of the Planning Act.

The application is assessed against the E01 assessment outcomes and mandatory assessment requirements, the district policy for the block, the technical specifications as benchmarks, and the Crown lease. A lease that authorises one dwelling will usually need a lease variation, which is itself a listed use in the Land Use Table and part of the same approval process.

RZ1 is where most dual occupancy questions arise, because it is the suburban zone that covers most of Canberra's detached housing. The technical specifications set a maximum dwelling density for multi-unit housing on an RZ1 block: 54 dwellings per hectare for attached houses and 67 for apartments. The note explains the arithmetic, block size in square metres divided by 10,000 and multiplied by the per hectare figure, rounded up.

Density is a specification, so it works as a benchmark for assessment outcome 5 rather than an absolute bar. Site coverage is different. E01 assessment requirement 8 is mandatory and caps multi-unit housing at 45% of the original block area in RZ1 and RZ2, and 50% in RZ3, RZ4 and RZ5. Original block area means the block as first leased, so a block that has already been split does not get a fresh allowance.

Storeys are also mandatory. E01 requirement 6 gives RZ1 a maximum of 2 storeys for everything, and in RZ2 multi-unit housing may reach 3 storeys. The building height figure in metres sits in the technical specifications and is covered in the height and setback guide.

Beyond the mandatory requirements, a dual occupancy must satisfy the E01 assessment outcomes, which cover site and land use, access, amenity, built form, sustainability and parking. The policy explains how the specifications fit: consideration is given to the relevant design guides and may be given to the technical specifications as a benchmark, and where a proposal complies with the specification and comprehensively addresses the outcome, no further assessment of that outcome is required.

This is the outcome-based approach that Part A describes as a distinctive feature of the Territory Plan. A proposal that meets every number in the technical specifications has a strong presumption of approval on those outcomes. A proposal that departs from a number can still be approved, but the applicant has to demonstrate the outcome is achieved another way, and the district policy's own requirements prevail if they are stricter.

The Dictionary's standard block definition also matters for RZ1. A standard block is one originally leased or used for one or two dwellings, or created by consolidating such blocks. Whether your block is standard or non-standard changes the unit titling rule below.

Two dwellings on one lease can be sold separately only after unit titling under the Unit Titles Act 2001 or a land subdivision under the Planning Act. The F01 Subdivision Policy governs both. Assessment requirement 12 permits unit title subdivision of multi-unit housing in RZ1 only where all dwellings have been lawfully constructed and either the block is a standard block of at least 600m² or it is a non-standard block. Staged unit title development is not permitted for fewer than five units.

Land subdivision in RZ1 is governed by requirement 11: creating additional blocks is permitted where each subdivided block contains a lawfully constructed dwelling, or each subdivided block is at least 350m². Requirement 8 adds that subdivision is only permitted where a new dwelling can be accommodated on the block in accordance with the Plan, or an existing lawful dwelling and any building on the consequent lease can be shown to comply.

Under the Unit Titles Act the lessee applies to the Territory Planning Authority, and the authority may approve the application only if the proposed use of each unit is permitted under the lease and consistent with any development approval. In practice that means the dual occupancy DA comes first, construction second, and unit titling last. The subdivision guide sets out these rules in full.