Building on land at risk of a natural hazard

Natural hazard dangers

The Building Act requires us to decline a building consent for work or major alterations to a building if:

• the land is subject to one or more natural hazards
• the work will accelerate or worsen the adverse effects of the natural hazard on that land or other property.

This would not apply if we are satisfied that adequate provisions have been made to protect land, building and other property or restore any damage to that land or other property.

If the building consent is approved, a condition would require a notice to be registered on the property title to ensure future owners of the land know about the potential hazard.

What is a natural hazard - according to the Building Act

The Building Act defines a natural hazard as land subjected to:

• erosion (including coastal erosion, bank erosion, and sheet erosion)
• falling debris (including soil, rock, snow, and ice)
• subsidence
• inundation (including flooding, overland flow, storm surge, tidal effects and ponding)
• slippage.

Hazards such as tsunamis or earthquakes are not regarded as natural hazards under the Building Act.

Occasionally natural hazards may not be identified in Project Information Memorandums (PIMs) associated with your building consents, and there may be a need for the BCA to determine whether or not natural hazard provisions apply.

The Ministry of Business, Innovation and Employment (MBIE) have recently produced a "Natural Hazards Decision Tree" associated with Determination 2017/048, which provides useful information in determining Natural Hazards responsibilities. Refer to Appendix B, Determination 2017/048 (PDF 330KB).

When you can build near a natural hazard

Building work may take place if:

• the natural hazard is sufficiently remote from the building work
• the hazard is deemed not to be "natural", as in the case of a constructed or designed overland flow path
• the alterations to the building are not major alterations (see AC2229 (PDF 216KB) for definitions)
• the land, building work, and other property can be protected
• you restore any damage to the land or other property as a result of the building work.