There isn’t a general rule saying every dual-occupancy dwelling must be at least, for example, 80 m² or 100 m².

You can therefore have one dwelling smaller than the other, provided both dwellings still achieve the applicable requirements for things such as private open space, parking, solar access, amenity and building design.

There is an important exception to keep in mind: specific size controls can apply for particular purposes. For example, ACT planning requirements have included a 120 m² maximum (excluding garage) for one dwelling in certain RZ1 dual-occupancy unit-title arrangements.

Reference: Planning (Residential Zones) Technical Specifications 2026 (NI2026–303) – Planning (Residential Zones) Technical Specifications 2026 | PDF

The DA needs to show how soil, mud and sediment will be kept on the property during construction instead of washing onto the road or into stormwater drains.

For sites under 3,000 m², the plan should show at least:

• sediment controls, such as sediment fencing;
• a stabilised site access point;
• a designated cutting/wash area; and
• the water-flow path, such as contours.

For a simple dual occupancy, this information can be shown on another plan rather than requiring a completely separate drawing. More complex developments may require a separate Erosion and Sediment Control Plan.

Reference: ACT Minimum DA Documentation Guideline 2026 (NI2026-13)

The DOR is essentially the document that explains why your dual-occupancy proposal should be approved under the Territory Plan.

Rather than just submitting drawings, the report explains how the proposal responds to the relevant planning requirements and Assessment Outcomes.

For a dual occupancy, the documentation guideline also separately identifies a Design Response as required. So the DOR and Design Response should not be assumed to be the same document.

Reference: ACT Minimum DA Documentation Guideline 2026 (NI2026-13)

Yes. ACT Planning can approve a Development Application subject to conditions that require changes to the plans or other documents originally submitted.

These conditions are generally used to make sure the development is consistent with the Territory Plan or relevant entity advice. You may need to amend a plan, drawing or other document and submit it to the Territory Planning Authority—or a relevant entity—for review and endorsement. Minor changes may sometimes be annotated directly on the approved plans.

Reference: ACT: Possible Outcomes – https://www.planning.act.gov.au/applications-and-assessments/development-applications/after-you-apply/possible-outcomes

Yes. You can withdraw a Development Application at any time before ACT Planning decides it. If major design changes are needed, withdrawing and lodging a new DA may be necessary where the revised proposal is too different from the original application. Under the Planning Act 2023, an applicant may withdraw a DA at any time before it is decided.

Before withdrawing, you may be able to amend the existing DA instead. However, ACT Planning will only accept an amendment where the amended development is substantially the same as the original proposal and satisfies the other amendment requirements. If the changes are not substantially the same, ACT Planning states that a new DA is required for the amended proposal.

Reference: Planning Act 2023 – section 183, Withdrawal of development applications – https://www.legislation.act.gov.au/View/a/2023-18/current/html/2023-18.html

No. A neighbour’s objection—formally called a representation—does not automatically prevent a Development Application from being approved.

ACT Planning must consider representations made during the public notification period, particularly where they raise relevant planning issues such as privacy, solar access or traffic. However, ACT Planning expressly states that a DA decision is not based on the number of representations received; it is the content and planning relevance of the representations that matters.

A relevant objection may result in ACT Planning requesting further information, imposing conditions, requiring changes, or ultimately refusing the proposal—but an objection by itself does not determine the outcome.

Reference: ACT Planning – After You Apply – Planning Act 2023