The planning system does allow new homes to be built in areas at risk of flooding, but only in very specific circumstances.
The National Planning Policy Framework advises that development should be directed away from the areas at the greatest risk of flooding. Where development is necessary in flood plains, it should be designed to be safe from flood events - and without simply displacing flood water and increasing the risk of flooding elsewhere.
For planning purposes, the risk of flooding is determined using the Environment Agency’s “Flood Map for Planning”, which divides the country into three different zones depending on the likely risk.
Sites in Flood Zone 1 are those with a low-risk of flooding, less than 1 in 1,000 annual probability. At the other end of the scale, sites in Flood Zone 3 have more than a 1 in 100 chance of flooding each year. This third flood zone includes the “functional flood plain” - areas of land where water is stored during flood events. The map also identifies those areas of land which are protected by defences.
National policy can sometimes be quite vague on how its requirements should be interpreted, but in the case of flood risk there are quite specific steps which should be followed.
Firstly, when deciding where to locate development, councils should follow a sequential approach to flood risk. That means first looking for suitable sites in Flood Zone 1 before considering sites in Zone 2 if enough appropriate land can’t be found. If enough sites aren’t identified, sites in Flood Zone 3 can then be considered. This is known as the sequential test.
If the outcome of the sequential test is that homes have to be built in an area at risk of flooding - either Flood Zones 2 or 3 - then you need to show how the development will be made safe in the event of a flood. That includes demonstrating that the risk of flooding elsewhere won’t be increased - if the ground levels on a site are just raised above the likely height of flooding, then that water will flow - and flood - somewhere else instead. You also need to prove that the sustainability benefits to the community outweigh the risk of flooding- this is the exception test.
There are a variety of measures that can be used to make a new housing development safe. In its simplest guise, the floor level of homes can be raised above the likely height of any flooding. This is usually accompanied by a flood storage area, ensuring the overall amount of water that the site will hold isn’t changed and making sure nowhere else floods instead.
Other solutions can relate to minimising the damage flooding will cause to homes, such as raising plug sockets and electrical wiring above the likely flood level.
This approach should be followed by councils both when they’re making local plans and when they’re deciding planning applications.
Local plans guide development in an area for a 15-year period, therefore they often need to identify sites for a large number of new homes. When deciding where they are to be located, councils should take account of the sequential test. This might influence how many homes are planned for specific settlements within a borough - if one town is at a high risk of flooding, is it better to direct development towards another town which isn’t?
It might not be possible to deliver all the new homes that are needed in towns and villages that aren’t at risk of flooding.
If a site at risk of flooding is allocated for housing development, then the eventual planning application should set out how the exception test will be met.
For planning applications on sites that don’t have a development allocation, a sequential test would need to be carried out showing that there aren’t any other suitable sites at a lower risk of flooding.
Although it is possible to secure planning permission for new housing developments on sites that are at risk of flooding, planning policy is tightly written and requires clear demonstration as to why new homes must be built on that site, and how they will be made safe.
While the planning system is complex, with the right expertise it is possible to secure planning permission for more complicated sites.
The Strategic Land Group is a land promotion company specialising in securing planning per-mission on all types of sites, at our cost and risk. If we don’t succeed, it doesn’t cost you anything. Our return is a share of the value of the site once it is sold.
We’re always on the lookout for new sites, so if you own land you’re interested in selling, we’d be delighted to hear from you.
