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Assess flood risk for your business premises

Quick assessment of flood risk exposure for your premises - check flood zone, identify required actions, and understand insurance implications.

Starting Updated 3 November 2026

Flood risk assessment for your premises

Three steps to understand your flood risk exposure and what you need to do about it.

Check your flood zone
Assess flood risk and SuDS compliance

Find your flood zone and understand what assessments or approvals apply to your site.
Flood zones at a glance

Your flood zone determines how urgently you need to act and what assessments are required.
In England, planning policy (National Planning Policy Framework, Annex F) sorts land into Flood Zones by the probability of river or sea flooding. The Environment Agency's Flood Map for Planning shows them. Your development proposal must show how it will manage flood risk through the planning system.

Flood Zone 1

Low probability: less than 0.1% (1 in 1,000) a year from rivers or the sea

Flood Zone 2

Medium probability: 1% to 0.1% a year from rivers, or 0.5% to 0.1% from the sea

Flood Zone 3a

High probability: 1% (1 in 100) or more a year from rivers, or 0.5% (1 in 200) or more from the sea

Flood Zone 3b

Functional floodplain: land where water has to flow or be stored in times of flood

Flood Risk Assessment (FRA) requirements
Include a site-specific FRA with a planning application for any development, including minor development and changes of use, that is:
in Flood Zone 2 or 3, including Flood Zone 3b
in Flood Zone 1 on a site of 1 hectare or more
in an area the Flood Map for Planning shows as "Flood Zones plus Climate Change"
in Flood Zone 1 where the Flood Map for Planning shows a risk of surface water flooding, whether present or future
in an area with critical drainage problems

FRA prepared by

Usually a flood risk specialist; simple, low-risk development such as a house extension may be done yourself

Consultation

Council consults the Environment Agency or lead local flood authority for some developments, and uses national standing advice for others

Consultee response period

21 days, unless a longer period is agreed
Flood risk zones and development requirements in Wales

Flood zones on the Flood Map for Planning in Wales and when a development needs a Flood Consequences Assessment under Technical Advice Note 15.

In Wales, Technical Advice Note 15 (TAN 15) sets planning policy on flood risk. The Flood Map for Planning, published by Natural Resources Wales, is the starting point. It shows flood zones for rivers, the sea, and surface water and small watercourses, together with TAN 15 Defended Zones.

Flood Zone 1

Less than 0.1% (1 in 1,000) annual chance of flooding, including climate change

Flood Zone 2

Rivers and surface water: 1% to 0.1%; sea: 0.5% to 0.1% annual chance, including climate change

Flood Zone 3

Rivers and surface water: more than 1%; sea: more than 0.5% annual chance, including climate change

TAN 15 Defended Zones

Areas where formal defences give at least 1 in 100 (rivers) or 1 in 200 (sea) protection, plus climate change and freeboard

Flood Consequences Assessment (FCA)

If you propose development in Flood Zone 2 or 3, or in a TAN 15 Defended Zone, you must carry out a Flood Consequences Assessment proportionate to the nature and scale of the development. An assessment is also needed outside these zones if the development could affect the flow of surface water or water from ordinary watercourses.

Flood map

Flood Map for Planning (Natural Resources Wales)

Assessment

Flood Consequences Assessment, proportionate to the development

Surface water advice

The planning authority seeks the lead local flood authority's views where relevant
Identify required actions

Protect your business from flooding

Practical resistance and resilience measures, flood plan creation, and warning sign-up.

Take note

If you are in Flood Zone 2 or 3, sign up for free Environment Agency flood warnings immediately.
Check your insurance position
Flood Re does not cover businesses

The government-backed Flood Re scheme covers residential properties only. Commercial premises must obtain flood insurance on the open market.
Flood Re is a reinsurance scheme set up under Part 4 of the Water Act 2014. It helps insurers offer the flood cover in home insurance for households at high flood risk. It covers homes, not business premises.

Purpose

Keep flood cover in home insurance available and affordable

Covers

Homes, not business premises

Eligible homes

Built before 1 January 2009

Council tax band

A to H, or equivalent

Where it applies

England, Wales, Scotland and Northern Ireland

Planned end

2039

Use of the scheme

Your insurer decides whether to pass the flood risk to Flood Re

What this means for business premises
Insure business premises on the commercial insurance market. Flood Re does not cover:
farm outbuildings
bed and breakfast premises that pay business rates
blocks of more than three flats
blocks or portfolios of properties insured to earn commercial income
Part of a mixed-use property can still qualify. For example, a farmhouse dwelling can be passed to Flood Re if the insurer can separate the dwelling from the commercial risk and the dwelling meets the criteria.
gov.uk
Check your long-term flood risk (opens in a new tab)

Free Environment Agency service - enter your postcode to see river, sea, and surface water risk

Official guidance

National Planning Policy Framework, Annex F: Managing flood risk and coastal change (opens in a new tab)

GOV.UK · England

Flood risk assessments - climate change allowances (GOV.UK guidance) (opens in a new tab)

Environment Agency · England

Coastal Change Management Areas guidance (opens in a new tab)

MHCLG · England

Flood risk assessments: applying for planning permission (opens in a new tab)

Environment Agency · England

Technical advice note (TAN) 15 (opens in a new tab)

www.gov.wales · Wales

Flood Re eligibility criteria (opens in a new tab)

Assess flood risk for your business premises

Flood risk assessment for your premises

Check your flood zone

Assess flood risk and SuDS compliance

Identify required actions

Protect your business from flooding

Check your insurance position

Check your long-term flood risk (opens in a new tab)

Official guidance

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