Flood Zone C is land with a low probability of river or coastal flooding, and it is where most development, including housing, is normally considered appropriate without needing the Justification Test. A Zone C classification does not rule out other flood sources such as surface water or groundwater flooding.
Zone C covers the majority of land in the country and represents low fluvial and coastal flood probability. The sequential approach in the guidelines directs development towards Zone C in preference to Zones A and B, and applications there are not normally subject to the Justification Test on flood grounds.
It is important to understand what Zone C does not tell you. The zones are derived from river and coastal flood modelling, so a Zone C site can still be affected by surface water ponding, blocked drainage, groundwater flooding or a small watercourse that has not been modelled.