Pre-Purchase checks for Potential Flooding when Buying a home

When purchasing a property you need to be mindful that severe weather events are becoming a fact of life in Brisbane which, being built upon a flood plain is prone to flooding especially during the summer storm season from November through to March. 

While you're doing your pre-purchase due diligence you might also like to consider Brisbane City Council's range of free tools and information to help you understand the property's potential flood risk.

It's also a good idea to take a close look at the landscape surrounding the property. For example, large established trees may harbour termites, may cause cracking and movement by affecting drainage or may pose a power or structural risk if felled during storms. The state of the houses immediately surrounding your property may show symptoms of fungal decay or mould with poor drainage or even cracking with movement. You also need to consider the proximity of any water sources. According to the Brisbane City Council, flooding may be caused by rivers, creeks, storm tide and overland flow.

Overland flow is excess rainfall runoff from homes and driveways before it enters a creek or stream, after a creek or stream breaks its banks, or after rising to the surface naturally from underground and tends to affect localised areas. It can be unpredictable and its severity will depend on the amount of rainfall. However, its impact is best understood by looking closely at the flow path through your property. Where does the house sit in relation to the land? Do paved or concreted areas slope towards the house? Do gardens impede the flow, trapping water around the base of the house?

Creek flooding happens when water from roofs, driveways, parks, footpaths and other surfaces makes its way via the underground storm water network into creeks and waterways. Heavy rainfall can cause creek levels to exceed their capacity, flowing over their banks into properties, roads and parks.  Storm surge can also cause creek levels to rise often quickly, without warning.

River flooding happens when widespread, prolonged rain falls over its catchment area.  As the river reaches capacity, excess water flows over its banks, causing flooding. The effects of this may not be experienced downstream until hours after rain, where the severity of flooding will depend on the speed and volume of water. The impact upon homes will depend on their proximity to the river and how high they have been built above ground level.

Low lying bay suburbs near the foreshore are particularly susceptible to storm tide flooding which occurs when a storm surge resulting from a low pressure system coupled with strong onshore winds creates higher than normal sea levels.  

Flooding can also occur from king tides which occur regularly throughout the year but most typically in the mornings over a few days in January.  King tide information is predictable and readily available in tide books.

In summary, whenever purchasing a property anywhere near rivers, creeks, the foreshore, tide-affected areas, and other waterways you need to be mindful that it may be susceptible to flooding. This is very important especially as many home and content policies do not cover flood damage or have specific limitations on the definition of a flood.  So it's essential that you read your insurance policy very carefully or contact your insurer to discuss home and contents insurance.

If you believe your property you are purchasing may have had previous storm damage ensure your building inspector is aware and can asses the building. Contact us for more information about pre-purchase inspections or book your building and pest inspection online now.