Questions & Answers

When does an attached secondary residence become a dual occupancy?

A secondary residence is different from a dual occupancy because it is a smaller dwelling that is subordinate to the main dwelling.

If the development no longer meets the requirements for a secondary residence — for example, the second dwelling exceeds the applicable 90 m² maximum size or the development is instead proposed as two dwellings without a principal-and-subordinate relationship — it may need to be considered as a dual occupancy (multi-unit housing).

Dual occupancy is therefore assessed under different planning requirements from a secondary residence.

Reference: Territory Plan 2023 – Part E01 Residential Zone Policy –  Territory Plan 2023 | Notifiable instruments

Last reviewed: 14 September 2026 Information current as at: 16 September 2026

Short Answer

A secondary residence must be subordinate to the main dwelling and meet the applicable secondary residence requirements, including the 90 m² maximum size. If the proposal instead consists of two dwellings that do not meet the secondary residence requirements, it may be treated as a dual occupancy (multi-unit housing).

Detailed Explanation

The classification of a development as a secondary residence or dual occupancy is determined by the applicable land-use definitions and requirements under the Territory Plan.

A secondary residence must be subordinate to the principal dwelling and satisfy the applicable secondary residence requirements, including the maximum dwelling size of 90 m², excluding the garage.

Where a proposed second dwelling does not satisfy the definition or applicable requirements for a secondary residence, the development may instead constitute multi-unit housing comprising two dwellings (dual occupancy) and must be assessed against the applicable multi-unit housing provisions.

Key Point

No minimum block size does not remove the need for planning assessment.

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