What an overlay is
An overlay is a layer on a council or state planning map. It marks land that planners consider affected by a hazard, and it usually brings extra rules for building work: floor heights, materials, setbacks or a permit for works that wouldn't otherwise need one.
An overlay is not a forecast that the house will flood or burn. And the absence of one is not a clean bill of health. Maps are updated slowly, often miss overland flow from heavy rain, and are drawn for planning, not insurance.
Where to check, by state (as at October 2026)
NSW
- NSW Planning Portal Spatial Viewer. Search an address to see the planning controls that apply and generate a property report.
- Section 10.7 planning certificate. Issued by the council. The 10.7(2) certificate lists constraints including flooding and whether the land is bushfire prone. One is normally attached to the contract, so read it, not just the first page of the contract.
- NSW Flood Data Portal. Run by the NSW SES and the state environment department, it holds flood studies and floodplain risk management plans. The council is still the main source of flood information for a property.
VIC
- VicPlan. Search an address and create a planning property report, which lists every zone and overlay that applies.
- Overlays to look for. The Land Subject to Inundation Overlay (flood fringe and storage areas in a 1 in 100 year flood), the Floodway Overlay, the Special Building Overlay (stormwater flooding in urban areas) and the Bushfire Management Overlay.
QLD
- Council flood mapping. Each council runs its own. Brisbane's FloodWise Property Report, for example, shows river, creek, storm tide and overland flow flooding, with flood levels for events from a 20% to a 0.2% annual chance.
- State Planning Policy interactive mapping system. The state's searchable map of planning layers, including natural hazard mapping.
- The council planning scheme. Flood and bushfire overlay maps sit inside it.
SA
- SAPPA (the South Australian Property and Planning Atlas) on PlanSA. Search an address to see which Planning and Design Code overlays apply, including the Hazards (Flooding) and Hazards (Bushfire Risk) overlays.
- Mapping is being updated. Draft state-wide flood hazard changes were open for consultation from 21 May to 13 August 2026, and a state-wide bushfire overlay update is still awaiting a decision. Mapping for an address can change after you buy.
Insurance
Insurers use their own hazard models, not planning overlays, so a house without an overlay can still carry a high premium and the reverse can happen too. Flood risk can make a large difference. The Actuaries Institute found in August 2023 that riverine flood risk made up more than half the home insurance premium for about 171,000 households, and that premiums for the highest-risk properties had risen by about 50% in a year.
At the top end of risk, some addresses attract few insurers or only very expensive cover. That's why it pays to get an indicative insurance quote on the address before you commit, not after.
Lending and resale
A lender may ask more questions about a property with significant hazard exposure, or about one that can't be insured on normal terms. Your mortgage broker can tell you how lenders treat a specific address.
Resale is the quieter risk. The next buyer will see the same maps and get the same insurance quotes. Some owner-occupiers will simply cross the house off their list, and a smaller buyer pool tends to mean longer selling times and weaker prices.
What an overlay does and doesn't mean
| It does mean | It doesn't mean |
|---|---|
| Planners consider the land affected by a mapped hazard | The house will flood or burn |
| Extra rules may apply to renovations, extensions or rebuilding | The house can't be renovated |
| Insurance and resale should be checked more closely | The house is a bad buy |
| Part of the lot may be affected | The dwelling itself is necessarily affected |
Detail matters. A flood overlay over the back corner of a long block is very different from one over the house. In a bushfire area, the Bushfire Attack Level (BAL) for the site affects what any rebuild or extension must meet.
How we use it
Hazard checks happen at the pocket and house levels, before a property reaches a client. A mapped hazard isn't automatically a no, but it has to be priced in, insurable at a sensible cost, and something we're comfortable the next buyer will accept too.
Our due diligence checklist puts these checks in order with everything else, and the inspection checklist covers what to look for on site, from water marks to vegetation close to the house.
Sources
- Eurobodalla Shire Council, "Section 10.7 planning certificate", accessed October 2026
- NSW Department of Planning, "Using the Spatial Viewer", 2022
- NSW Environment and Heritage, "NSW Flood Data Portal", July 2024
- Planning Victoria, "VicPlan", updated October 2026
- City of Yarra, "Overlays planning factsheet", December 2024
- Brisbane City Council, "FloodWise Property Report", accessed October 2026
- Queensland Government, "State Planning Policy", updated September 2026
- PlanSA, "Hazard mapping project", accessed October 2026
- Actuaries Institute, "Home insurance affordability update and funding for flood costs", August 2023
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