Ōtepoti Dunedin (Monday, 17 March 2025) – Minimum floor level requirements for new homes and building extensions in low-lying coastal parts of Dunedin are set to be increased to better protect against flooding due to sea level rise.

The new requirements set by the Dunedin City Council (DCC) will come into effect today, and are the first update to coastal minimum floor level requirements since 2011. The latest update sets a new minimum floor level of between 3.05m and 3.17m above sea level in certain areas.

DCC Customer and Regulatory Acting General Manager Paul Henderson says the DCC, like all other Building Consent Authorities, is required to ensure all new builds comply with the New Zealand Building Code. This includes considerations for protections against flooding from weather events and sea level rise.

The change to the requirements primarily affects floor levels, as well as building foundations, sub-floor structures, on-site septic tank and waste systems, and surrounding land areas. Due to these structures also being at risk of being affected by sea level rises, protections for them should also be taken into consideration when applying for building consent.

The new minimum floor levels have been set based on future climate change projections and apply to most low-lying coastal areas.

In some cases where the building or the land around it are not adequately protected from natural hazards including flooding caused by rain events and sea level rise, building consent may need to be granted with a natural hazard notice placed on the property’s record of title. This only applies to the construction or major alteration of buildings. The notice ensures that future owners and other interested parties are made aware that the hazard is likely to occur during the building’s economic lifespan, which is 75 to 80 years.

“We’re aware this may affect some new builds which are already part-way through the planning stage,” Mr Henderson says.

“We’ll work with any affected parties to find a solution to help them with their build. This may mean we consider reducing consent application fees to offset extra costs in situations where plans need to be revised.”

More guidance information, including maps of affected areas, is available on the DCC website.

The Ministry of Business Innovation and Enterprise recently published a guidance document highlighting the importance of the land around the building work.

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