Short answer: yes on an eligible lot, and without a planning application, but Moreton Bay runs it on two separate tests that are easy to mix up: one asks whether your lot is even eligible to carry a granny flat, the other caps how big it can be. Under the MBRC Planning Scheme 2016 (the City of Moreton Bay's operative scheme), a granny flat (the scheme calls it a secondary dwelling) is accepted development subject to requirements when the lot passes eligibility and the design meets the requirements checklist, and a missed requirement is handled narrowly, on that matter alone, not as a rejection.
The eligibility test: can your lot carry a secondary dwelling at all
Before size ever comes into it, the lot has to clear a minimum-size-and-frontage gate (PO21/E21 in Part B of the Dwelling house code 9.3.1; the same gate sits in Part A as requirement RAD18). The scheme's own words, from PO21:
"Secondary dwellings only occur on lots with minimum dimensions of: a. in the Suburban neighbourhood precinct or Coastal communities precinct of the General residential zone - a lot size of 600m² and a primary frontage width of 12.5m; b. in all other applicable precincts, zones or local plans - a lot size of 450m² and a primary frontage width of 10m."
The figure depends on precinct: 600 m² and 12.5 m of frontage in the Suburban neighbourhood or Coastal communities precincts, or 450 m² and 10 m of frontage everywhere else the use applies, including the Next generation neighbourhood precinct. This is purely an eligibility gate; it says nothing about the secondary dwelling's size, which is the mix-up the next section clears up.
The size cap, and why it is smaller than the eligibility figures suggest
Once a lot is eligible, the maximum gross floor area is set by the lot's area, not its frontage. The scheme's own words (RAD21 in Part A of the Dwelling house code 9.3.1; the identical wording sits in Part B as E21C):
"Secondary dwellings have a maximum gross floor area of: a. 45m², where located on lots between 450m² and 800m² in area; or b. 55m², where located on lots greater than 800m² in area."
So a 600 m² lot in the Suburban neighbourhood precinct clears eligibility but is still capped at 45 m², sitting below the 800 m² threshold; only lots over 800 m² reach 55 m². An older reading of this rule, keyed to primary frontage rather than lot area, does not appear in the current scheme text and should not be relied on. The secondary dwelling also has to stay substantially smaller than the primary dwelling (PO21C), and against neighbouring South East Queensland councils that also key their granny-flat caps to lot area, this 45 m² to 55 m² band sits at the smaller end. One point favours the applicant: these figures cap the no-application pathway only; where the lot already needs an application for another reason, a larger secondary dwelling can be pursued through it, assessed as remaining subordinate to the primary dwelling.
What else the requirements checklist covers
Beyond eligibility and size, the code's checklist covers, among other things: the two dwellings share a single water connection and meter, electricity connection and meter, wastewater connection, street number and letterbox, driveway and pedestrian access point to the lot; at least one extra car space beyond the primary dwelling's requirement; the unit is not sited in front of the primary dwelling, annexed or freestanding within 10 m; only one secondary dwelling per lot; a freestanding unit in the Suburban neighbourhood or Coastal communities precincts orients its entry and outdoor living toward the primary dwelling; and on-site open space and allocated parking stay accessible to the occupants of both dwellings. The shared-services rule is where a second water meter or driveway trips a design without anyone intending it to.
Miss a requirement: it narrows, it does not kill it
Worth understanding before you spend money on a design: every requirement above carries the same verbatim note attached to it in the scheme, tying it to the state's own concurrence framework:
"a planning scheme matter for which Council will exercise a concurrence agency role for a building development application"
(Under Division 2, Part 3, Schedule 9 of the Planning Regulation 2017, as the note applied to each secondary dwelling requirement in the Dwelling house code 9.3.1 puts it.)
In plain terms: a missed requirement is handled narrowly, on that matter alone, not as a full merits fight over the whole proposal. The scheme carries two routes for that narrow handling, Council's concurrence role on the building application quoted above, and the code's own rule that a missed requirement changes the category to assessable development limited to the unmet matter, and which route operates for a given miss is exactly what a town planner confirms for your specific proposal before you rely on it. That is softer than it sounds, though it is not a free pass: it still means council scrutiny on that point.
Flood and coastal overlays: when a granny flat needs an application
Only flood hazard and coastal hazard can change a Moreton Bay assessment category, and for a dwelling house (the use class a secondary dwelling sits within): no change in the Balance flood and Balance coastal planning areas, where the flood or coastal codes still apply as building-stage benchmarks; code assessment in the Medium and High risk flood areas (the scheme states plainly that a dwelling house is code assessable in the Medium risk area; the High risk rows apply outside the Limited development zone) and in Medium and High risk storm tide areas (High again outside the Limited development zone); and code assessment across the board in an erosion prone area. Land mapped in a Drainage investigation area is also lifted to code assessment. Beyond flood and coastal, non-category overlays (environmental areas, overland flow paths, heritage and landscape character, riparian and wetland setbacks, scenic amenity, transport noise corridors, infrastructure buffers, extractive resources (separation areas and transport routes)) attach values-and-constraints requirements to the Dwelling house code; missing one drops the accepted pathway to code assessment limited to that matter. Bushfire and landslide hazard sit outside this: both are policies, not overlay codes, so they do not change the assessment category, and instead bite at building stage through construction standards.
If the lot does not qualify, dual occupancy is a different product, not a substitute
Where a lot cannot clear the secondary dwelling eligibility test, some owners look at dual occupancy (duplex) instead, and it is worth being precise about what changes. A secondary dwelling is not separately saleable; it stays on one title with the primary dwelling. A dual occupancy is two dwellings that can be sold separately, through a building format community title over the approved building, itself its own solicitor or planner-advised process, while the underlying land stays one lot. In the Next generation neighbourhood precinct, dual occupancy is accepted development where the lot has part of its primary frontage within 800 m walking distance of a higher-order or district centre or a train station, or two or more road frontages and at least 450 m², or otherwise at least 15 m of frontage and at least 500 m², and a code assessable application where none of the three is met; in the Suburban neighbourhood precinct the test is instead a lot of 1,000 m² or more for code assessment, and impact assessment below it. These are different eligibility numbers on a different product, not an interchangeable fallback.
How to check your own block
- Find your parcel on the City of Moreton Bay's ePlan, confirm its zone and precinct, then check lot area and frontage against the eligibility test for that precinct.
- If eligible, set the GFA cap from lot area alone (45 m² between 450 m² and 800 m², 55 m² above), and check the design stays substantially smaller than the primary dwelling.
- Check the flood and coastal overlay maps, and any other overlay (environmental, overland flow, heritage, riparian, scenic, noise, infrastructure buffer) that could attach a values-and-constraints requirement.
This page is general information about the City of Moreton Bay planning scheme, not advice about your property. Overlay effects vary lot by lot, planning schemes amend, and the council's current scheme prevails. Do not rely on this page for a specific property. Get a site-specific report or independent professional advice before acting. We work with town planners, not in place of them: where a pathway depends on design or professional judgement, a town planner or the relevant qualified professional confirms it for your specific proposal.
Want the answer for your block? Our $690 site-specific report reads the zone, the precinct, every overlay mapped on the property and the surviving development pathways for one property, with every figure cited to the scheme. Not ready for that? Start with the free development risk checklist, read our Moreton Bay planning and zoning guide, or check whether your block can instead be subdivided.
Sources: MBRC Planning Scheme 2016 (the council's official ePlan), including the Dwelling house code (9.3.1: Part A RAD18 to RAD25; Part B PO21/E21, PO21C/E21C), Tables 5.5.6.2.1 and 5.5.6.3.1 with the Residential uses code (9.3.2) for the dual occupancy comparison, Part 5.10 (Categories of assessment, overlays), and Schedule 9, Part 3, Division 2 of the Planning Regulation 2017 (Qld). Everything on this page comes from the council's own published planning scheme; we explain it in plain English. The scheme text itself is the authority.
Published by LandIntel. How we research: our methodology.
Verified 3 to 7 July 2026 against the MBRC Planning Scheme 2016, Version 7.1 (effective 23 June 2025); schemes amend, and the live scheme prevails.