Flood Zone A is the classification for land with the highest probability of river or coastal flooding. Under the national flood risk guidelines, highly vulnerable development such as housing is generally considered inappropriate in Zone A unless it passes the Justification Test set out in those guidelines.
Zone A represents the highest flood probability band used in the guidelines. Because housing is classed as highly vulnerable development, a proposal for a dwelling in Zone A faces a strong policy presumption against it. Water-compatible uses such as open space, docks and some agricultural uses can be appropriate there.
Where development is proposed in Zone A, the guidelines require the Justification Test to be applied. This is a demanding test that considers whether the development is required by planning policy for the area, whether the site is in a zoned and serviced location, and whether flood risk can be managed to an acceptable level.