MBRC Planning Scheme - Dwelling houses in Flood hazard areas

The Flood hazard overlay map only impacts you if your property is identified on the map and you wish to develop (i.e. building or extending, changing use, subdividing, clearing vegetation, filling or excavation).

The Flood Hazard overlay map identifies areas impacted by flood that pose a potential risk to people and property. The Flood Hazard overlay code is found in section 8.2.2 of the planning scheme and includes the requirements for development occurring on land identified on the overlay maps according to their level of risk.

The overlay map and code are designed to ensure people and property in these areas are safe from flash flooding and river flooding events.

There are three areas that make up the Flood planning area shown on the Flood hazard overlay map:

  1. Balance flood planning area
  2. High risk flood area
  3. Medium risk flood area.

For further information about this overlay, see the information sheets.

This information sheet provides a summary of the requirements for building or extending a Dwelling house (including Domestic outbuildings and Secondary dwellings) in areas identified on the Flood hazard overlay map. The requirements vary depending on which area the proposed house is located.

Dwelling houses in the Balance flood planning area

If your property is mapped in the Balance flood planning area (outside the High and Medium risk flood hazard areas) building a new Dwelling house or extending a Dwelling house will be either accepted development or accepted development subject to requirements.

Extending an existing Dwelling house by 50m2 or less is accepted development, meaning there will be no planning scheme requirements, provided the building work satisfies the circumstances for being accepted development in Table 1.7.7.1 Accepted development of the planning scheme.

Building a new Dwelling house or extending an existing Dwelling house by more than 50m2 (including domestic outbuilding and secondary dwelling) in the Balance flood planning area is accepted development subject to requirements, meaning it must comply with the requirements in the Flood hazard overlay code. The requirements include:

  1. Build to minimum habitable floor level1;
  2. Use waterproof materials for non-habitable areas below the minimum habitable floor level;
  3. Ensure filling does not impact on water flows or other properties during the Defined Flood Event (DFE)2.  Filling is allowed in the Balance coastal planning area as a minimum to the Flood planning level; and
  4. Hazardous chemicals are located and stored at or above the minimum habitable floor level1.

In the event you do not comply with these requirements, a development approval is required from Council.

These requirements are summarised from RAD2 to RAD6 of the Flood hazard overlay code.

Dwelling houses in Medium and High risk flood hazard areas

All new buildings, including extensions 50m2 and less in area, are not to be located in the High risk flood hazard area that is also included in the Limited development zone.

Building a new Dwelling house or extending a Dwelling house by more than 50m2 (including domestic outbuilding and secondary dwelling) in the Medium and High risk flood hazard areas requires development approval from Council. The assessable (code assessment) application will need to demonstrate how the proposal is designed to mitigate the intolerable and tolerable risks of the flood hazard in accordance with the Flood hazard overlay code.

The following requirements from the Flood hazard overlay code apply to both new Dwelling houses and extensions (including domestic outbuilding and secondary dwelling) in the Medium and High risk flood hazard areas:

  1. Build to minimum habitable floor level1;
  2. Utilise pier and pole constructions to achieve minimum habitable floor level;
  3. Undertake structural design of the dwelling using a suitable engineer;
  4. Ensure the building work is capable of withstanding the nature of the hazard(s) which the building may be subject to;
  5. Use waterproof materials below the minimum habitable floor level;
  6. Ensure fencing is at least 50% permeable;
  7. Ensure building design addresses the street;
  8. Demonstrate that the works won't cause flooding to other properties; and
  9. Filling is not permitted in the High risk area or Medium risk areas except for the creation of stormwater infrastructure such as detention basins, bioretention and levees.

These requirement are summarised from performance outcomes PO1 to PO4 and Table 8.2.2.4 Fill requirements of the Flood hazard overlay code.

Queensland Development Code MP3.5 Construction of buildings in flood hazard areas also applies in the Medium and High risk areas.

Dwelling houses in a Drainage Investigation Area (DIA)

The Flood hazard overlay code identifies Drainage Investigation Areas (refer to Figures 8.2.2.1 to 8.2.2.10 at the end of section 8.2.2 Flood hazard overlay code). My Property Look Up also identifies if a property is in a DIA. These areas identify where further development may be possible subject to investigations confirming building design, earthworks, drainage and/or infrastructure solutions that can mitigate likely flooding impacts.

Building a new Dwelling house or extending a Dwelling house by more than 50m2 (including secondary dwellings and domestic outbuildings) in a DIA requires development approval from Council. The assessable (code assessment) application will need to demonstrate compliance with relevant requirements for that part of the High or Medium risk flood hazard area in which the Dwelling house is to be located.

Building or extending a Dwelling house does not trigger the requirement to prepare a drainage master plan for the area. All other forms of development in a DIA will however trigger an impact assessable application and the requirement to prepare a drainage master plan.

How do I find out if my property is mapped in the Flood hazard overlay?

Use the free online My Property Look Up. If there is no reference to the overlay then it does not apply to your property. You can also utilise Council’s interactive mapping to view applicable overlays through Planning Scheme Maps. The Flood hazard overlay impacts your property if it is identified in the mapping and you wish to develop.

More information

View information sheets:

Information about the Defined Flood Event and Flood Planning Level can be obtained via a Flood Check Development Report.

For further information about flood behaviour, download a free Flood Check Report. A Flood Check Property Report will provide information on the extent and depth for a number of flood and storm tide events relevant to your property of interest. A Flood Check Development Report will provide information required to support the planning scheme for the Flood and Coastal hazard overlays. These reports do not map risks associated with development and therefore cannot be directly compared to the mapping shown on any overlay.

1. Minimum habitable floor heights are located, designed and constructed to:

  • 300mm above the Defined Flood Event (DFE) for sites east of the Bruce Highway and outside the Erosion Prone Area.
  • 500mm above the Defined Flood Event (DFE) for sites east of the Bruce Highway and inside the Erosion Prone Area overlay.
  • 750mm above the Defined Flood Event (DFE) for all sites west of the Bruce Highway.

Refer to Schedule 1, Table SC1.2.2 - Administrative definitions for definition of 'Habitable floor level'

2. The DFE is the event used to determine the flood level for planning and development purposes.

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