Building in a flood prone land or a flood zone can be a very risky and costly exercise.  Given the associated risks with the build, a lot of builders usually shy away from building your home in these flood affected areas.

However, if you can find a builder who knows what they are doing, your home building journey will be far smoother and safer.

To get a good understanding if your block is flood affected or not, it’s important to know where to look for this type of information.

Flood Information

NSW Planning Portal

NSW Planning Portal:  this is a fantastic tool for you to check your build address and what can potentially be affecting it.  It’s not 100% accurate, but it’s a great place to start.

10.7 Certificate

10.7 Certificate:  this is one of the most important document and will tell you all the potential issues that affect your block.  Flood is certainly one of them.  Below is a snapshot of a 10.7 Certificate for a block of land that is affected by flood:

Flood Maps

Flood Maps:  another useful tool is to check your local council website for flood mapping (if available) to check if your building block is in that map.  Below is an example of what a flood map could look like.

3 Things to avoid

1)  First Timers

If you are building a home in a flood affected block of land, avoid first timers.  That is, builders who have never built a home in a flood affected block of land.

Let me assure you, they have no idea.  You will be their experiment, their first guinea pig.  I am not sure about you, but I would hate to be experimented on with my own money.

It’s important that you find a builder who has already built in flood affected land and get references from them.  Check these references and drive by to double check all is well and true.

2)  Of course we can

If the builder tells you that they can build anything and it’s no problem at all, then ask them about their process for building in flood affected land.  If they have a specific process and their consultant understand how it all works, then that is a good start.

It’s important that you also understand what the process looks like or should look like.

Building in a flood zone is a complicated and a very involving process.  As much as you should trust your builder, you must also learn and understand what it means to be building in a flood prone block of land to ensure things are done correctly and promptly.

3)  Volume & Small Builders

Volume or large builders generally do not like building these type of builds.  It takes longer to investigate upfront, longer to have them approved, longer to plan, longer to build and not to mention the complexity of it all.

Hence they try and avoid it at all costs.  Needless to say, they may not be the best fit for you.  This does not mean that you won’t find a volume builder who is good and actually wants to do this sort of build, but it’s unlikely.

When it comes to small builders, just avoid them altogether.  Whether it’s a flood affected or not, I would never ever recommend building with a small builder.  The lack of financial backing, material costs, labour costs, length they take to complete a project, lack of processes, etc… AND then you throw a complex flood affected build in the mix.  Not a great combo…

The 3 Tips

Ok, so you have a flood affected block of land.  You want to build a home.  Below are the 3 tips that I strongly recommend you follow:

1)  Be Prepared

You must be prepared mentally and emotionally to take on this journey.  Anything that could go wrong with your home building journey may go wrong.  If you don’t have the emotional or mental strength to deal with the stress of it all, then this is not for you.

I don’t care what any builder tells you, I have done enough of these types of builds to tell you that something always go wrong.  This doesn’t mean that it cannot be fixed etc…; on the contrary, everything has a solution.  It will just take the time it needs to and it will cost you what it needs to cost you!

It would also work in your favour if you did your homework.  It’s important that you are informed, as much as you can, and be willing to learn as part of your home building journey.

2)  Investigation Process

This is an important part of the journey.  The upfront process that your builder follows is super important.  ALL the investigations must happen upfront and not at a later stage.  That way, you know what you are getting yourself into.

Below are some of the required reports that your builder MUST obtain upfront:

  • Contour Surveys
  • 10.7 Certificate
  • 88b Instrument
  • Flood Study / Flood Certificate
  • Soil Test
  • Engineering Reports
  • Hydraulics

The above are not exhaustive but they are the bare minimum to start with.  Now, there is a process on how to use these reports and of course your builder must know this.

They should have an understanding, taking into account the abovementioned reports, of your local controls to provide you with a home design that works on your flood prone block of land.

If this does not happen upfront, then you are asking for trouble.  Some builders will just sign you up, put some provisional allowances and move you to the next stage to deal with this.  Unfortunately you are in too deep and paid them so much money that you cannot really walk away.

This process will cost you some money.  It’s not a choice.  But then again, you are building a complex build – it costs money to investigate and make sure that you get all of your research upfront.

Now there are occasions where a builder can use provisional allowances in matters relating to flood, but they are very rare.  If you are ever in doubt, always double check the information provided!

3)  FFL

It’s important that you have supporting documents to show your finished floor levels (FFL), otherwise council may not approve your build.  Some councils have done studies which they will allow you to use.

Other councils will require you to obtain your own flood studies using flood engineers.  They may have a recommended list or your builder will certainly work with one.

So it’s important to know these upfront as it will determine how high you have to lift your home.


It’s a costly exercise to build in a flood prone land.  Subject to size of the footprint, it could add upwards of $75,000+ to your build cost.

As fast as you want to go, do not rush your builder and work with them to find solutions to potential problems rather than work against them.  As long as the builder is doing the right thing of course.

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