FRA Approval Process: Timeline and What to Expect
From instruction to planning approval — what happens at each stage of the flood risk assessment process and how long each step takes.
One of the most frequent frustrations we hear from developers is that the flood risk assessment process took longer than expected. In most cases, the delay was not caused by the assessment itself but by a misunderstanding of the steps involved and the time each one requires.
This guide walks through the FRA process from initial instruction to planning decision, setting out what happens at each stage, who is involved, and how long each step typically takes. Whether you are planning a single dwelling or a major strategic site, understanding this timeline will help you programme your project accurately.
Stage 1: Instruction and Scoping (Week 1)
The process begins when you instruct your flood risk consultant. At this stage, the consultant will:
- Review the site location, flood zone, and available flood mapping.
- Identify the flood sources that affect the site (fluvial, tidal, surface water, groundwater, sewers).
- Determine the appropriate level of assessment (desktop or detailed with modelling).
- Confirm whether an EA data request is needed.
- Provide a fee proposal and programme.
For a straightforward desktop FRA, scoping takes a day or two. For a complex site that may require modelling, allow a week for the consultant to review the available data and confirm the scope.
Key action for you: Provide the consultant with the site boundary (ideally as a shapefile or georeferenced plan), the proposed development description, and any pre-application advice you have received from the LPA or EA.
Stage 2: EA Data Request (Weeks 2-6)
If the site is in Flood Zone 2 or 3, the consultant will typically submit a data request to the Environment Agency. This request asks the EA to provide any existing flood modelling data, flood defence information, and recorded flood outlines for the site and surrounding area.
The EA’s standard response time for data requests is 20 working days (four weeks), although in practice it can take up to six weeks during busy periods. This is often the longest single step in the process and the one most commonly underestimated.
The data request is critical because it determines what existing information is available. If the EA has a recent, detailed model that covers the site, flood levels can be extracted from that model and no new modelling is needed — saving significant time and cost. If no suitable model exists, bespoke modelling will be required.
Key action for you: Instruct the FRA as early as possible to allow time for the data request. Do not wait until the design is finalised — the FRA should inform the design, not follow it.
Stage 3: Assessment and Modelling (Weeks 3-12)
Once the EA data has been received, the consultant can proceed with the assessment. The timeline for this stage depends entirely on whether modelling is required.
Desktop FRA (No Modelling): 1-2 Weeks
For a desktop flood risk assessment, the consultant will review the EA data, analyse the flood risk from all sources, assess climate change impacts, consider the Sequential and Exception Tests if applicable, and prepare the FRA report. This typically takes one to two weeks of active work.
Detailed FRA with Modelling: 4-10 Weeks
For a detailed FRA involving hydraulic modelling, the timeline is longer and involves several sub-stages:
- Model build (2-3 weeks): Constructing the hydraulic model using LiDAR, survey data, and the EA’s existing model structure where available.
- Calibration and verification (1-2 weeks): Checking the model against recorded flood events or observed water levels to ensure it is producing reliable results.
- Design scenario runs (1-2 weeks): Running the model for a range of return periods (1 in 100 year, 1 in 1000 year) and climate change scenarios.
- Post-processing and mapping (1 week): Generating flood extent, depth, velocity, and hazard maps from the model results.
- Report preparation (1-2 weeks): Writing the FRA report, integrating the modelling results with the policy assessment, mitigation recommendations, and drainage strategy.
For complex sites with multiple flood sources, breach modelling, or extensive sensitivity testing, this stage can take up to 12 weeks.
Stage 4: Draft Report Review (1-2 Weeks)
Before the FRA is submitted with the planning application, most consultants will issue a draft report for client review. This allows the developer and their design team to:
- Check that the site description and development proposals are accurately described.
- Review the recommended mitigation measures and confirm they are compatible with the design.
- Raise any queries about the findings before submission.
Allow one to two weeks for this review stage. It is important not to skip this step — errors in the submitted FRA can trigger EA objections and delay the planning decision.
Stage 5: Planning Submission (Week Variable)
The completed FRA is submitted as part of the planning application package. The timing of submission is usually determined by the overall project programme rather than the FRA itself. However, it is worth noting that the FRA should be submitted at validation — not as a later addendum. LPAs will typically refuse to validate an application in Flood Zone 2 or 3 without the FRA.
Stage 6: Statutory Consultation (Weeks 1-8 Post-Submission)
Once the planning application is validated, the LPA will consult the relevant statutory bodies. For flood risk, the key consultees are:
- Environment Agency: Consulted on all applications in Flood Zones 2 and 3, and on major developments (10+ dwellings or 1,000+ sqm) in Flood Zone 1. The EA’s standard response time is 21 days, but complex sites may take longer.
- Lead Local Flood Authority (LLFA): Consulted on surface water drainage for major developments. Response times vary by LLFA but are typically 21 to 42 days.
- Internal Drainage Board (IDB): Consulted where the site is within or discharges to an IDB district.
If the EA or LLFA raises an objection, the consultant will need to address the concerns — often through additional modelling, revised mitigation, or supplementary information. This can add four to eight weeks to the programme depending on the nature of the objection.
Stage 7: EA and LLFA Sign-Off
The objective is to secure a “no objection” response from the EA and LLFA. This means they are satisfied that the FRA adequately assesses the flood risk, that the proposed mitigation is appropriate, and that the development will not increase flood risk elsewhere.
In some cases, the EA may recommend planning conditions rather than raising an objection. Common conditions include requirements for finished floor levels, flood resilience measures, or a detailed surface water drainage scheme to be submitted and approved before construction begins.
Total Programme: Summary
| Scenario | Typical Duration |
|---|---|
| Desktop FRA, no modelling, no EA objection | 6 - 10 weeks |
| Desktop FRA with EA data request and consultation | 10 - 16 weeks |
| Detailed FRA with modelling and EA consultation | 16 - 26 weeks |
| Complex FRA with EA objection requiring resolution | 26 - 40 weeks |
These timescales assume a single round of consultation and a co-operative EA response. If the EA raises a sustained objection that requires significant additional work, or if the modelling reveals issues that require redesign of the development, the programme can extend further.
How to Minimise Delays
- Instruct the FRA at pre-application stage: Do not wait until the planning application is ready to submit. The FRA should be one of the first technical workstreams commissioned.
- Use EA pre-application advice: A free discussion with the EA will confirm their expectations and reduce the risk of objections.
- Integrate flood risk into the design: Work with your consultant to use the FRA findings to inform the site layout, not just to justify a fixed design.
- Allow realistic timescales: Do not compress the FRA programme to fit an arbitrary submission deadline. Rushed work leads to EA objections and longer delays.
- Choose an experienced consultant: A consultant with a strong relationship with the EA and LLFA can navigate the process more efficiently. At Aegaea, we work with regulators daily and understand what they expect to see. Contact us to discuss your project timeline.