A flood risk assessor is a MCIWEM or MRICS-qualified specialist who prepares Flood Risk Assessments (FRAs) for planning applications. An FRA is required by the National Planning Policy Framework for all development in Flood Zones 2 and 3, and for development over 1 hectare in Flood Zone 1. The assessor evaluates flood risk to the proposed development, assesses the impact of development on flood risk elsewhere, and demonstrates how risks will be managed - including through building design, raised floor levels and sustainable drainage (SuDS).
What they do
- Review Environment Agency flood maps and historic flood records
- Carry out site-specific flood level assessments
- Prepare Flood Risk Assessments for planning applications
- Carry out hydraulic modelling where required
- Prepare Sequential Test and Exception Test evidence
- Design sustainable drainage systems (SuDS)
- Liaise with the Environment Agency and Lead Local Flood Authority
- Discharge flood risk planning conditions
When you need one
Check the Environment Agency Flood Map for Planning before purchasing land or submitting a planning application. An FRA is required in the following circumstances.
Typical costs (UK, 2025)
| Service | Typical cost |
|---|---|
| Basic site-specific FRA | £800 - £2,000 |
| Detailed FRA with hydraulic modelling | £2,500 - £8,000+ |
| Sequential Test report | £500 - £1,500 |
| SuDS drainage strategy | £800 - £2,500 |
| Flood risk insurance report | £400 - £900 |
| Hourly rate | £75 - £130 / hr |
Complex sites in Flood Zone 3 with hydraulic modelling requirements can cost significantly more. Engage the Environment Agency pre-application service early to understand their requirements.
Qualifications to look for
The primary qualification for flood risk specialists. MCIWEM members working in flood risk typically have degrees in hydrology, civil engineering or environmental science. Check membership at ciwem.org.
Chartered surveyors with a flood risk specialism may also prepare FRAs - particularly for simpler residential applications in lower-risk flood zones.
Specialists with postgraduate training or experience in hydrology are well placed to carry out hydraulic modelling and more complex FRAs near watercourses.
How to find a reputable flood risk assessor
Frequently asked questions
What is a Flood Risk Assessment?
A report that identifies the flood risks to and from a development, assesses the impact of the development on flood risk elsewhere, and shows how risks will be managed - including through the design of the building, raised floor levels, and sustainable drainage systems (SuDS). Required by the NPPF for development in flood zones and for larger sites in low flood risk areas.
What are the flood zones?
Flood Zone 1 is the lowest risk - less than 0.1% annual probability of flooding from rivers or sea. Flood Zone 2 is medium risk (0.1-1% river or 0.1% sea flooding). Flood Zone 3a is high risk (over 1% river or 0.5% sea flooding). Flood Zone 3b is the functional floodplain where water flows and storage during flooding is needed. Check the Environment Agency flood map at environment.data.gov.uk.
What is the Sequential Test?
A planning policy test that requires local authorities to steer development to lower flood risk sites wherever possible. Sites in higher risk zones can only be approved if there are no suitable alternatives in lower risk zones. For residential development in Flood Zone 3a and 3b an Exception Test must also be passed, demonstrating that the development will be safe for its lifetime and will not increase flood risk elsewhere.