Scientists are observing changes in our climate. Climate change will likely decrease yearly rainfall and create more storms.

National engineering guidelines, known as Australian Rainfall and Runoff 2019, inform how stormwater mapping should consider climate change. These guidelines suggest creating maps that show how rainfall will increase because of climate change.

Requirements to prepare stormwater maps come from engineering guidelines and specifications. The information includes details about drains, the shape and slope of the land, and land development. Specialist engineers, who have prepared stormwater maps for other councils, did the work. Separate reviewers check their work. For more information see the Technical Report (5.5MB).

Property values are determined by many factors. These factors include things like trends in interest rates, finance availability, changing property markets, demographic trends, location desirability, types of nearby properties, amenities, and services in the neighbourhood. Property characteristics and features are also relevant factors. This includes lot size, style and age of the property, renovation potential, and the layout of indoor and outdoor spaces.

To better understand the potential impact, Council contacted other municipalities where stormwater maps exist to find out if any additional information was available.

In 2016, Manningham City Council worked with specialist property advisors to give independent advice on whether their stormwater map would affect property values of the affected areas. Stonnington City Council did a similar assessment in 2004.

Both expert advisors found no connection between stormwater maps and property values, whether in the short or long term.

We recommend you talk to your insurance provider about your insurance policies.

The Insurance Council of Australia (ICA) represents the insurance industry. Their website gives information about insurance matters. The ICA website says:

“… Storm or rainwater cover in your insurance policy may cover the situation where your house becomes inundated by rainwater that has fallen naturally from the sky. Though most insurers regard rainwater runoff as part of storm cover, some insurers won’t cover rainwater runoff or storm surge when the customer chooses not to take flood cover. These options are explained in the product disclosure statement for your policy.”

Council's Storms and Flooding Preparedness webpage gives information about this.