Flood Risk AssessmentsFrom £395
How much does a flood risk assessment cost in London?
A flood risk assessment for a London planning application costs our fixed £395, with no VAT charged. Whether you need one at all depends on the flood zone your site sits in, and we check that on the Environment Agency's flood map first, so you only pay for a report the council will require.
The short answer: one fixed fee, and a check before you pay
Our flood risk assessment costs £395. We check your address on the Environment Agency's flood map for planning, give you the flood zone and surface water risk result, test the vulnerability of your proposed use against the zone, and write a site-specific assessment in the structure councils expect, as a PDF to go with the application.
If the check shows your site does not need an assessment, we say so, and you do not buy one. A drainage note is added where the scheme could affect drainage.
- Check the flood map
Your address is checked on the Environment Agency's flood map for planning for its zone and surface water risk.
- Decide if one is needed
The result is tested against the rules to see whether an assessment is required at all.
- Test the use
The vulnerability of your proposed use is set against the flood zone.
- Write the assessment
A site-specific assessment is written in the form councils expect, with a drainage note if needed.
When one is required
Environment Agency guidance says you should complete a flood risk assessment for development proposed in Flood Zones 2 or 3, including minor development and changes of use, and for development in Flood Zone 1 with a site area of 1 hectare or more. Most London homes are on sites far smaller than a hectare, so the flood zone is what decides it.
The same guidance sets out an exception: for a simple, low-risk development, for example a house extension, you may be able to do it yourself, and a minor extension is a household or non-domestic extension with a floor space of no more than 250 square metres. We tell you which side of that line your project is on, which sometimes means the honest answer is not to buy a full report from us.
Rivers, drains and the drainage strategy
Proximity to water matters even in a low-risk zone. The guidance asks applicants to find out whether the development is within 20 metres of a main river or flood defence, which can bring the Environment Agency into the application.
It also says you need to include a sustainable drainage strategy if your development could affect drainage on or around the site. A new paved garden room base or an extension over a soakaway can do that, and our note on drainage sits inside the fixed fee rather than being added after the assessment.
What the assessment does for the application
On a flood zone site the council needs the assessment to judge the application, so a missing one is a reason for delay. A good one sets out the risk to the site, what the proposal does about it, and how surface water from the roof and paving is dealt with.
It does not guarantee the council will grant permission, and it does not replace the council's own consultation with the Environment Agency. It gives the officer what they need to decide.
Where it sits in the budget
A flood assessment is one of several documents that can accompany a planning application. The post on rear extension drawings explains the main drawing fee and the council's, and our post on feasibility studies shows how to find out early whether your site has a flood zone problem.
Our flood risk assessment page shows the service in detail.
Sources
Every figure in this article, where it comes from and a link to the original.
- in Flood Zones 2 or 3: Environment Agency, Flood risk assessments: applying for planning permission: you should complete a FRA for all development (including minor development and changes of use) proposed (source wording: "in Flood Zones 2 or 3"). www.gov.uk
- 1 hectare or more: Environment Agency, Flood risk assessments: applying for planning permission: (source wording: "within Flood Zone 1 with a site area of 1 hectare or more"). www.gov.uk
- house extension: Environment Agency, Flood risk assessments: applying for planning permission: (source wording: "An exception to this may be if it is for a simple, low risk development, for example, a house extension"). www.gov.uk
- no more than 250 square metres: Environment Agency, Flood risk assessments: applying for planning permission: (source wording: "A minor extension is a household or non-domestic extension with a floor space of no more than 250 square metres"). www.gov.uk
- within 20 metres of a main river or flood defence: Environment Agency, Flood risk assessments: applying for planning permission: find if the development is (source wording: "within 20 metres of main river or flood defence"). www.gov.uk
- sustainable drainage strategy: Environment Agency, Flood risk assessments: applying for planning permission: (source wording: "You need to include a sustainable drainage strategy if your application is for development: which could affect drainage on or around the site"). www.gov.uk
Questions people ask
Do I need one for a house extension?
Do I pay VAT on your fee?
Is the council fee included?
What if my site is in Flood Zone 3?
Does it cover drainage?
Photographs: Paul Bryan (Unsplash License); Martti Salmi (Unsplash License).
Flood Risk Assessments: a fixed fee from £395
Read more on the flood risk assessments service page, or send your address below and we reply within one working day.
Flood Risk Assessments
from £395
Every price is the full fixed fee you pay. No VAT is charged. Council application fees are paid to the council separately.
What you get
- A check of the site on the Environment Agency flood map for planning
- A flood zone and surface water risk result for the address
- The vulnerability classification of your proposed use, tested against the zone
- A written site-specific assessment in the structure councils expect
- The assessment as a PDF for the planning application