How to Check Flood Risk for Any NSW Property

Many parts of NSW flood regularly — not just coastal areas, but river floodplains, creek catchments, and even some urban suburbs with poor stormwater drainage. A flood classification does not prevent a purchase, but it significantly affects your costs, your building options, and your insurance.

Flood classification affects:

• What you can build or renovate on the land
• The floor level height you must build to
• Your ability to get home and contents insurance, and how much it costs
• The long-term resale value of the property
• Your access to the property during and after a flood event

In NSW, flood risk mapping is done by individual councils. Each council commissions a flood study — a technical analysis of how water flows across the land during storm events of different sizes.

The most common flood categories you will see are:

• High flood risk (floodway): The main path water travels during a flood. Building here is usually severely restricted or prohibited.
• Medium flood risk area: Land that may be inundated in significant events. Category names vary by council — check your Section 10.7 certificate for the exact classification.
• Low flood risk: Affected only in larger, less frequent flood events. Building is generally permitted with conditions (such as minimum floor heights).

The 1-in-100-year flood event (also called the 1% AEP — Annual Exceedance Probability) is the standard benchmark. A property in the 1% AEP flood zone has roughly a 1% chance of experiencing that level of flooding in any given year — but that does not mean it only floods once a century. Over a 30-year mortgage, the cumulative probability of experiencing at least one such event is around 26%.

The most reliable source for NSW flood information is the NSW Planning Portal. The Planning Portal's mapping tool lets you search any NSW address and see the flood overlay layers applied by the local council.

For current flood intelligence and local catchment information, the NSW State Emergency Service (SES) publishes flood plans and local emergency information for communities across NSW.

Individual councils also publish their flood studies and floodplain risk management plans on their websites. These are the technical documents behind the flood maps — useful if you want to understand exactly how an area was assessed.

The definitive legal document for flood classification (and all other planning constraints) is the Section 10.7 planning certificate. This is an official document issued by the council that lists every planning restriction that applies to a property.

There are two types:

• Section 10.7(2): The basic certificate — lists zoning and key constraints.
• Section 10.7(5): The full certificate — includes all additional planning overlays including flood, bushfire, and contamination.

Ask your conveyancer to obtain a Section 10.7(5) certificate as part of your pre-purchase due diligence. It is issued by the council and is the most authoritative source of planning information for that specific property.

Properties in flood zones can be harder and more expensive to insure. Before you buy, get insurance quotes for the property — not just a generic quote, but one specific to that address. Some insurers will decline to cover flood risk in high-risk areas, while others will cover it at a significant premium.

The Australian Government's Disaster Assist website has information about flood insurance in Australia, including the standard definition of "flood" (which can vary between policies).

DueDili pulls flood overlay data directly from the NSW Planning Portal and displays the flood classification for each NSW address in the report. You can see at a glance whether a property sits in a flood planning area and the category of risk assigned by the council.

This is a useful first check — but always verify with a Section 10.7 certificate and talk to your conveyancer before exchanging contracts. Run a free report for any NSW address.

For suburb-level flood context, check the area profiles for nearby suburbs.