Minor Development

In England, a FRA is required when the development or site is located in Flood Zone 2 and 3 according to the Environment Agency flood map for planning. An FRA is also required if the Site is in Flood Zone 1 when it is equal to or greater than 1 hectare in size or if it’s located within a Critical Drainage Area, regardless of its size.

Even with this in mind, the National Planning Policy Framework requires an FRA to be used to assess all sources of flooding. Therefore, an FRA could be requested even if your site doesn’t fit these requirements. Especially if there is a history of flooding, such as from a sewer or reservoir.

If your site is within 20 meters of an Environment Agency (EA) Main River, it’s also highly likely you’ll be required to provide an FRA with a particular focus on the EA Guidance.

Use the Environment Agency’s Flood Map for Planning, which is free to access. You define your site boundary and it returns the flood zone classification, along with surface water and climate change data. In Scotland, use SEPA’s flood maps; in Wales, the Flood Map for Planning published by Natural Resources Wales.

On the EA map, light blue shading is Flood Zone 2 and dark blue is Flood Zone 3. Either means your site is at risk of flooding and a Flood Risk Assessment will be required. An application submitted without one will likely be rejected, so it is worth checking at the idea stage rather than after the design is fixed. Finding out late can mean costly changes, from raising floor levels to relocating buildings on the site.

Bear in mind the maps show risk from rivers and the sea. They do not show Flood Zone 3b, and they will not tell you about groundwater or sewer flooding, so a clear result does not always mean no assessment is needed. Plenty of sites outside Flood Zones 2 and 3 still require an FRA.

Being in a flood zone does not end your development plans. Our team has supported many complex projects, including large developments in Flood Zone 3b, the highest risk classification in the English planning system. If you are unsure which flood zone your site falls in, or whether the project is viable, get in touch.

Flood zones classify land by the annual probability of river and sea flooding. They are defined in Annex F, table 1 of the NPPF and mapped by the Environment Agency on the Flood Map for Planning. Flood Zone 1 is less than 0.1%. Flood Zone 2 is between 1% and 0.1% from rivers, or 0.5% and 0.1% from the sea. Flood Zone 3a is 1% or more from rivers, or 0.5% or more from the sea. Flood Zone 3b, the functional floodplain, is where water has to flow or be stored in floods, identified by the council in its strategic flood risk assessment.

There are a lot of different parameters that can influence the time it takes to complete an FRA. Each project is unique and has different flood risks, designs, environmental conditions, topography, historic uses, and are subject to different planning policies. All of these can affect the time it takes for a flood risk assessment to be completed. The industry standard for an FRA is around 4 to 6 weeks.

Our team, however, have experience in supporting over 4,100 projects and have developed methods and techniques to analyse data efficiently and effectively review every aspect in a timely manner. On average, our FRA reports take 5 to 10 working days once we have received the necessary data.

In very limited cases, it may be possible for simple, low-risk developments such as small extensions. However, most planning applications require a professional consultant to ensure the assessment is accurate, proportionate, and meets planning policy requirements.

No. Most small developments in Flood Zone 1 do not need one, and a household extension built over an existing footprint that connects into existing drainage is often exempt. The requirement bites where the site is in Flood Zone 2 or 3, is one hectare or more in Flood Zone 1, sits within a Critical Drainage Area, lies within 20 metres of a Main River, or has known surface water, groundwater or drainage risk. Even outside those, a planning authority can still ask for one where flood risk or drainage constraints are present.

Yes, if your property sits in Flood Zone 2 or 3, or within a Critical Drainage Area. Size does not exempt you, and a planning application submitted without one is likely to be refused.

There is a common exception on the drainage side: an extension built over the existing footprint that connects into existing drainage may not need a separate drainage strategy. That is not the same as being exempt from a Flood Risk Assessment, so it is worth checking both.

If the property is in Flood Zone 1 and the site is under a hectare, you probably do not need one, though the local authority can still ask if there is a history of flooding nearby.