Flood Risk Consultants in the UK

Browse 207 verified flood risk consultants across the UK. Get quotes for Flood Risk Assessment, Sequential Test, Exception Test and more.

207 verified flood risk consultants across the UK on The Planning Review.

What does a flood risk consultant do?

A flood risk consultant assesses the risk of flooding to and from a proposed development and produces the technical evidence needed to satisfy planning policy. For any site in Flood Zone 2 or 3, and for major developments even in Flood Zone 1, the National Planning Policy Framework requires a site-specific Flood Risk Assessment (FRA) as part of the planning application. The consultant evaluates all sources of flooding (fluvial, pluvial, tidal, groundwater, and sewer) and designs mitigation measures that keep the development safe for its lifetime without increasing flood risk elsewhere.

A critical part of the role is navigating the sequential and exception tests. The sequential test requires the applicant to demonstrate that the development cannot reasonably be located in an area of lower flood risk, and a poorly evidenced sequential test is one of the most common reasons for refusal in flood-affected areas. Where the sequential test is passed but risk remains, the exception test requires proof of wider sustainability benefits and that the site-specific FRA shows the development will be safe. The flood risk consultant prepares the evidence for both tests and liaises with the Environment Agency, Lead Local Flood Authority (LLFA), and internal drainage boards on the applicant's behalf.

Beyond the FRA, flood risk consultants design surface water drainage strategies (typically incorporating SuDS), calculate climate change allowances for future flood risk, set finished floor levels, and specify flood resilience measures for buildings. Their technical evidence is frequently the deciding factor in whether a planning application in a flood-affected area is approved or refused.

When do you need a flood risk consultant?

  • The site is in Flood Zone 2 or 3, where a site-specific FRA is a mandatory validation requirement
  • The proposal is a major development (10+ dwellings or 1 hectare+) in Flood Zone 1
  • The LLFA's surface water flood maps show risk on the site, even if it is mapped as Flood Zone 1 for river flooding
  • The Environment Agency has objected to a previous application on the site on flood risk grounds
  • You are changing the use to a more vulnerable classification (for example, commercial to residential) in Flood Zone 2 or 3
  • The development must pass the sequential test because it proposes a non-water-compatible use in Flood Zone 2 or 3
  • The site is near a watercourse, canal, or tidal water and the LPA has requested an FRA
  • The development is on or near existing flood defences and residual risk (breach and overtopping) must be assessed
  • An outline consent conditions the submission of a detailed FRA at reserved matters stage

Services you can get local quotes for

  • Drainage Strategy & SuDS Design
  • Flood Risk Assessment (FRA)

Frequently asked questions

How much does a Flood Risk Assessment cost?

For a straightforward residential development in Flood Zone 2 using existing Environment Agency data, an FRA typically costs £1,500 to £4,000. For larger or more complex sites in Flood Zone 3, or where bespoke hydraulic modelling is required, costs rise to £5,000 to £15,000. A sequential test statement is usually included within the FRA fee or charged as an additional £500 to £2,000. Surface water drainage strategies, if included in the scope, add £2,000 to £6,000 depending on site size and complexity. Bespoke hydraulic modelling for a river reach can cost £8,000 to £25,000+ depending on model complexity and length of watercourse modelled.

How long does the process take?

A standard FRA using existing Environment Agency data can be produced in 3 to 6 weeks, although the EA data request process itself can take 4 to 6 weeks, so early engagement is essential. FRAs requiring bespoke hydraulic modelling take 8 to 16 weeks depending on the complexity of the modelling and the availability of survey data (topographic survey, river cross-sections). The sequential test statement should be prepared early in the process, as it may require liaison with the LPA to agree the search area and site availability criteria.

What is the sequential test and how do I pass it?

The sequential test requires you to demonstrate that the proposed development cannot reasonably be located in an area of lower flood risk. The LPA defines the search area (typically the administrative area for housing, or a wider area for commercial development) and the applicant must show that there are no reasonably available alternative sites in a lower flood zone that could accommodate the development. Passing the sequential test requires a thorough and transparent site search, with clear justification for why each alternative site is not suitable, available, or achievable. A poorly evidenced sequential test is one of the most common reasons for planning refusal in flood risk areas.

Can I build in Flood Zone 3?

It depends on the vulnerability classification of the proposed development. Water-compatible uses and essential infrastructure can be located in Flood Zone 3a subject to an FRA. More vulnerable uses (such as residential) can be located in Flood Zone 3a only if the sequential and exception tests are passed. Highly vulnerable uses (such as basement dwellings or caravans for permanent residential use) should not be permitted in Flood Zone 3a. No development other than water-compatible uses and essential infrastructure should be located in Flood Zone 3b (functional floodplain). In all cases, the FRA must demonstrate that the development will be safe for its lifetime and will not increase flood risk elsewhere.

What are climate change allowances and why do they matter?

Climate change allowances are percentage increases applied to current flood levels and rainfall intensities to account for the projected effects of climate change over the lifetime of the development (typically 100 years for residential). The Environment Agency publishes these allowances by river basin district and epoch. For example, peak river flows in many areas must be increased by 20% to 70% depending on the risk category. These allowances directly affect the design flood level and therefore the required finished floor levels, flood storage volumes, and drainage design. Failing to apply the correct climate change allowances is a common reason for EA objection to FRAs.

Legal and regulatory framework

  • National Planning Policy Framework (NPPF), Chapter 14 — Meeting the challenge of climate change, flooding and coastal change
  • Planning Practice Guidance (PPG) — Flood Risk and Coastal Change
  • Flood and Water Management Act 2010
  • Environment Agency Flood Risk Standing Advice
  • Water Resources Act 1991
  • Land Drainage Act 1991
  • Non-statutory Technical Standards for Sustainable Drainage Systems (Defra, 2015)
  • The SuDS Manual (CIRIA C753)
  • Climate Change Allowances (Environment Agency)

Professional accreditations

  • Chartered Institution of Water and Environmental Management
  • Engineering Council
  • Institution of Civil Engineers
  • Royal Town Planning Institute
  • Society for the Environment

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