Why flood maps matter more now
The Auckland Anniversary floods in January 2023 and Cyclone Gabrielle weeks later damaged thousands of homes. Since then, insurers have priced flood risk more closely, and the council has assessed which properties face an ongoing risk to life.
Many of the homes that flooded were on the council’s flood maps. Checking them is one of the most useful things you can do before you buy.
The four flood maps
| Map | What it shows |
|---|---|
| Flood plain | Land a river or stream would cover in a flood with a 1% chance of happening in any year (often called a 1-in-100-year flood), allowing for heavier rain in future. |
| Flood-prone area | Dips in the ground where water pools if pipes block or overflow. The council estimates how deep the water could get. |
| Flood-sensitive area | Land just above the flood plain, which a bigger flood could still reach. |
| Overland flow path | The route stormwater takes across the ground when pipes are full. Paths run downhill through many properties. |
You can see all four for any address with our flood risk check.
Check everything for one address, free
Flooding, the coast, land stability, zoning, planning rules and school zones, on one page. The full report with what to do next is $29.
See a sample reportWhat a 1-in-100-year flood really means
A “1-in-100-year” flood doesn’t happen once a century. It has a 1% chance in any given year, and can happen in back-to-back years. Over a 30-year mortgage, the chance of at least one is about 26%, roughly 1 in 4.
Planners call this a 1% annual exceedance probability (AEP). You’ll see both terms in council documents and LIMs.
What it means for buyers
- Insurance. Some insurers charge much more, add a higher flood excess, or decline cover for high-risk properties. Banks won’t lend without insurance.
- Building. New buildings and extensions in a flood plain must meet minimum floor levels, and you need consent to build over or block an overland flow path.
- Resale. Buyers increasingly check flood maps too, which can affect demand and price.
Being on a map doesn’t mean a house will flood. A flood plain may cover only part of a section, and many houses have floor levels well above the mapped flood level.
What to check
- Look at where the flood area sits compared with the house and garage, not just whether it touches the section.
- Ask the agent and neighbours whether the property flooded in 2023 or earlier.
- Read the LIM for recorded flooding and council notices, and check whether the property was assessed after the 2023 storms.
- Ask a building inspector to check floor heights, drainage and signs of past water damage.
- Get an insurance quote, including the flood excess, before you go unconditional.
Questions
Can I get flood insurance in a flood plain?
Usually, but it may cost more or come with a higher excess. A few high-risk properties struggle to get cover. Get a quote early.
Do overland flow paths affect value?
Many Auckland properties have one, and a path along a boundary is usually minor. A path running through the house or garage is more of a concern.
Where can I see the maps?
On Auckland Council GeoMaps, or for any single address with our flood risk check.