Guide
When you need a flood risk assessment for planning
Updated
A planning application needs a flood risk assessment when the site is in Flood Zone 2 or 3, is a Flood Zone 1 site of 1 hectare or more, or is at risk from surface water or future flooding. Without one, the council may refuse the application.
The Environment Agency's list
The Environment Agency's guidance for applicants says you should complete a flood risk assessment for all development, including minor development and changes of use, proposed in any of these places (gov.uk, flood risk assessment for planning applications):
- Flood Zone 2 or 3.
- Flood Zone 3b, the functional floodplain.
- Flood Zone 1, where the site area is 1 hectare or more.
- 'Flood Zones plus Climate Change', where the site is at increased risk from rivers or sea in future.
- Flood Zone 1, where the flood map shows a risk from surface water, now or in future.
- An area with critical drainage problems (currently only designated in Devon and Cornwall).
- Flood Zone 1, where the council's strategic flood risk assessment shows an increased risk over the development's lifetime.
- Development that increases the vulnerability classification and may be subject to flooding from sources other than rivers or sea.
The same page says the council may refuse an application that does not include a flood risk assessment, or whose assessment is not satisfactory.
Who writes it
The guidance says you will usually need to pay a flood risk specialist. The exception it names is a simple, low risk development such as a house extension, where you may be able to do it yourself. A minor extension is a household or non-domestic extension with a floor space of no more than 250 square metres, and it has its own standing advice.
What it costs
| Firm | Published price | What it is |
|---|---|---|
| Ashfield Solutions | from £250 + VAT | initial property flood report for planning |
| Flood Risk Environmental | from £295 | Flood Zone 1 FRA (simple statement) |
| Discount Plans Ltd | £340 to £380 | Flood Zone 1 to Flood Zone 3 |
| RIDA Reports | from £450 | flood risk assessment |
| Air & Flood Consultants | from £450 | small householder and minor development |
| Flood Risk Consultants | £500 to over £1,500 | flood risk consultant's report |
| Urban Water | from £650 | flood risk assessment |
| FloodPlan Reports | £650 | flood risk assessment |
| Enviropass | from £850 + VAT | flood risk assessment |
| GeoSmart Information | from £850 + VAT | flood risk assessment |
| FPS Environmental | £1,500 to £3,000 + VAT | smaller developments |
Source: Flood Risk Assessment Fee Index: every row, with its source