Flood risk assessment · London Borough of Wandsworth

Flood risk assessment in Wandsworth, from £375 fixed

Wandsworth's Policy LP12 sets the floor of new work 300mm above the 1 in 100 river level with climate change, keeps bedrooms above the extreme tidal level the Environment Agency advises, and does not permit self-contained basement homes in Flood Zones 2 or 3a. Our assessment works out which of those tests applies to your house.

Flood risk assessmentfrom £375

Get your fixed feeFFP-01 · Rev A

Drawing package

Borough or district

Property postcode

What you want to build

Our fixed feefrom £375

Council fee, paid to your councilNone

Total, our feefrom £375

CoverageAll 33 boroughs

Get this fee in writing

or email hello@fixedfeeplans.co.uk

No obligation. Nothing is sent until you ask; your enquiry comes to us and nowhere else.

Starts at£150

Boroughs33/33

Stages5

Photo: Derek Harper / Wikimedia Commons, CC BY-SA 2.0

Fixed fee, in writing

Tell us about your project

Send the postcode and what you want to build, and add photos or old plans if you have them. We reply with the fee in writing and the payment stages set out in full.

Name and email are required. Everything else helps us price it, but is optional.

What do you need drawn?

Borough or district

Name

Postcode

Phone

What are you planning to build?

Your enquiry goes to us and nowhere else. It is never syndicated or sold. See our privacy notice.

A red clad outbuilding with a white window standing in brown floodwater among bare trees — Flood-resistant materials are specified to a height above the estimated flood level. Photo: Serge Lavoie / Pexels.

What Wandsworth Council asks of a flood risk assessment

From the council's Wandsworth Local Plan 2023-2038, Policy LP12 (Water and Flooding) (adopted 19 July 2023).

In Flood Zones 2 and 3a, where the risk is fluvial, finished floor levels for all development must be raised to a minimum of 300mm above the 1 in 100 flood level, including an allowance for climate change. (source, checked 29 October 2026)
Where the risk is defended tidal flooding, all sleeping accommodation must as a minimum be on floor levels above the extreme water level advised by the Environment Agency, with safe access and egress at a Low Hazard rating. (source, checked 29 October 2026)
Self-contained residential basements will not be permitted in Flood Zones 2 and 3a, and bedrooms at basement level will not be permitted except as set out in the basement table of the policy. (source, checked 29 October 2026)
The local list asks for a flood risk assessment with every application in Flood Zones 2, 3a and 3b, and in Flood Zone 1 on land with critical drainage problems, land the SFRA shows at increased risk in future, or land where other sources of flooding meet a more vulnerable use. (source, checked 29 October 2026)

What Wandsworth flood risk assessment drawings have to show

In Wandsworth we first establish which kind of flood risk the house faces. Close to the Wandle the test is fluvial, and the extension floor goes 300mm above the 1 in 100 level with climate change. Nearer the Thames the risk is tidal and defended, so the question becomes where the bedrooms sit against the Environment Agency's extreme water level.

The assessment then carries the floor levels, the safe route out of the house and the resistance and resilience measures, and the plans show the same figures so the two documents agree.

PS2 · at a glance

Wandsworth: 977 householder decisions

Approvals, prior approvals included91.9%

898 of 977 granted. London: 85.8%.

Decided within 8 weeks90.9%

597 of 657 applications, prior approvals excluded.

Source: MHCLG PS2, 1 July 2025 to 30 June 2026. Dark tick: London.

Two hands holding a printed floor plan over a desk of drawings, with a pen and notebook beside it — Checking the drawings with you before anything goes to the council. Photo: Tima Miroshnichenko / Pexels.

What it costs in Wandsworth

Flood risk assessment: from £375.

Flood risk assessment across London · Wandsworth planning rules · every price

Flood risk assessment · Wandsworth

What happens next in Wandsworth

We check your address on every map the council uses, take the flood level with climate change, set the floor level and resilience measures, and mark them on the drawings.

Photo: Helena Jankovičová Kováčová / Pexels

Answers

Wandsworth flood risk assessment questions

When does Wandsworth ask for a flood risk assessment?

For all applications in Flood Zones 2, 3a and 3b, according to the council's local planning application requirements. In Flood Zone 1 it is also needed on land with critical drainage problems, land shown as at increased flood risk in future, or land where other sources of flooding meet a more vulnerable use.

Can I convert a basement into a flat in Wandsworth if I am in a flood zone?

Not in Flood Zone 2 or 3a. Table 15.1 under Policy LP12 says self-contained residential basements will not be permitted there, and bedrooms at basement level are not permitted except in the cases the basement table allows. A basement used as part of the house above is treated differently, depending on breach hazard.

What floor level does Wandsworth need for an extension in a flood zone?

Where the flooding is from a river, a minimum of 300mm above the 1 in 100 flood level including climate change. Where it is tidal and defended, the policy focuses on sleeping accommodation, which must be above the extreme water level advised by the Environment Agency, with a low hazard route out.

Start with £150

Your fixed fee is already on this page.

Tell us the postcode and what you want to build. We confirm the fee in writing and book the survey.

Get my fixed fee 020 7131 9703

Measured surveyWithin five working days

£150

Existing drawingsThe building as it stands

£175

Proposed drawingsYour scheme, revised until right

£225

Planning application packForms, statements, OS plans

£125

Submission and agent servicePortal submission, queries handled

£120

Total, planning application£795