Flood Risk – The predicted frequency of floods in an area
The flood put the house at risk every time (flood risk). The prospective owner asked "How often does this occur?"
A lot of rain falling in a short period of time can cause a flood – but there are further factors involved that make some areas more prone to flooding than others.
The topography – for instance, whether you are on a hillside or at the bottom of the valley – the ability of the land to soak up or impede movement of water, and the presence or lack of vegetation are all factors that affect the likelihood of flooding.
Apart from studying these factors, the risk of flooding in a particular area is based on statistics – how often floods have occurred there in the past.
In most countries, the relevant agencies keep maps that show the flood risk for each area. For instance, in the USA, the Federal Emergency Management Agency (FEMA) is the official public source for flood risk maps for insurance and other purposes.