How to Check Flood Risk in Australia — Verify an Address on Official Government Maps Before You Move, Rent or Buy
Before you rent or buy a home, here is how to use official government maps to check whether that address has flooded in the past or sits in a flood-risk area. Choose your state in the search below and you'll be taken to that state's official flood map. This guide explains the difference between the three kinds of flood maps (historical extent, hazard overlays, and real-time warnings), how to read them, and what else to check before signing a contract. AUWith does not judge whether any address is safe — always confirm for yourself on the official maps.
Why check flood risk
Australia is a flood-prone country. As with the major 2022 floods in the east, it is not only river flooding (riverine) that occurs — flash floods (flash flood), where short, intense downpours submerge inner-city roads and homes, are also common. Before you rent or buy a home, checking whether that address has flooded in the past or is designated as a flood-risk area can protect your insurance costs, your safety and your assets. Fortunately, each state government and local council (council) publishes free official flood maps. This guide shows you where to find those maps and how to read them.
What this guide can and cannot do
This guide helps you find the official flood map for the area you live in, understand what the map's markings mean, and know what else to check before signing a contract. However, AUWith does not judge whether a particular address is 'safe or dangerous.' Only official government maps and a council's planning certificate can make that determination. The search below simply points you to those official maps.
The three kinds of flood maps — don't mix them up
Flood information comes in three different forms, and mixing them up will lead you to the wrong conclusion. When looking at a map, first check which of the three you are actually viewing.
Why the three are kept separate
'It hasn't flooded before' does not mean 'it will be safe from now on,' and 'it isn't in a hazard zone' does not mean 'the flood study is complete.' You need to look at the three separately to be accurate.
- Historical flood extent (historical) — places that have actually been under water (for example, Brisbane in 1974 and 2011). But some flooding goes unrecorded, so 'no record = safe' does not hold.
- Flood hazard overlays (hazard / planning overlay) — risk zones calculated by modelling. These are often shown as '1% AEP' (a 1% annual chance, the so-called 100-year flood), which means not 'once in 100 years' but 'a 1% chance every year,' and it can even happen in two consecutive years.
Finding the flood map for your area
When you select your state below, you'll be taken straight to that state's official flood map viewer. If you enter an area name (suburb), a copy button will make it easy to paste into the viewer's address search box. Most official viewers offer their own address search, so once you open the viewer you can simply type the address into its search box.
AUWith does not determine whether an address is safe from flooding. Selecting your state below links you to the official government maps — before deciding to rent or buy, always re-confirm for yourself on the official maps and with the council's planning certificate.
Select a state to see the official flood map links for that state.
- Choose your state first. Flood maps are provided by a different government system in each state, so you'll be linked to the official viewer that matches the state you live in.
- Open the official viewer, then search for your address or suburb. Each viewer's search works a little differently, but most have an address search box at the top.
What to look for on the map
When you open an official map, zones are shown in colour. Focus on the four things below. Terminology and notation differ between viewers, so check each viewer's legend (legend) as well.
1% AEP means 'there is a 1% chance each year of a flood of about this size' (in older wording, a 100-year flood). 5% AEP (a 20-year flood) is a flood that happens more often. The larger the number, the more frequent the flood.
River flooding (riverine), rainfall/overland flooding (overland/stormwater), and coastal/tidal flooding (coastal/storm tide) have different causes. Some viewers, like Brisbane's FAM, break the display down by type, so check which type of hazard it is.
Some viewers also show the expected flood depth or the strength of water flow (hazard category). Even within the same 'hazard zone,' ankle-deep and roof-height are entirely different problems.
Even if there is no hazard overlay on the map, safety is not guaranteed. It may simply be that no flood study has yet been done for that area. If there is no marking, ask the council whether there is a flood study for that address.
Extra checks before renting or buying
Once you have a rough picture from the map, be sure to check the following before signing a contract. The map is a reference; the basis for legal and financial decisions is the official certificates and expert confirmation.
- Get a planning certificate — in NSW, the council's s10.7 certificate tells you about flood-related controls. Other states' councils issue equivalent planning/property information. It is essential when buying, and can also be requested when renting.
- Check the sale contract and disclosure. Seller disclosure obligations differ by state. Have a lawyer or conveyancer review the flood-related clauses in the contract.
Practical cautions
Misreading flood information can put your safety and a lot of money at stake. Be especially careful of the following.
- Don't believe 'flood-safe' claims in property ads. They are just the seller's or landlord's wording. Always cross-check on the official government maps and with the council.
- Don't trust old maps or screenshots. Flood studies and hazard overlays are updated (for example, the year noted on a 'Flood Risk Overlay'). Look at the latest version in the official viewer, not an old map frozen on a blog.
Reference links (flood data is updated, so check the latest version when you visit)
- Bureau of Meteorology — Australian Warnings(opens in a new window)
National flood warnings and forecasts from the Bureau of Meteorology (BOM). Check flood warnings for flooding that is currently under way or imminent, state by state. During the wet season you should look at these real-time warnings rather than a historical map.
- Geoscience Australia — AFRIP (Flood Studies)(opens in a new window)
Geoscience Australia's AFRIP — a national catalogue of flood studies. You can look up which government flood studies exist for your area (only areas where a study has been carried out are listed).
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