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Flood zones explained: Flood Zones 1, 2 and 3 in England, and how Wales and Scotland differ

What Flood Zones 1, 2 and 3 mean in England, how they affect planning permission, insurance and flood risk assessments, and why Wales and Scotland use different flood maps and different terms.

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Flooding is one of the most significant risks to property in the UK, and the planning system plays a central role in deciding where and how development takes place in flood-prone areas. Understanding what the flood maps say about a site matters for planning applications, insurance and property purchases.

The first thing to know is that "Flood Zone 1, 2 and 3" is an English system. Wales and Scotland each use their own maps and terms. The first half of this guide covers England. The nation notes near the end cover Wales and Scotland.

Flood zones in England

The Environment Agency maps three main flood zones for England on its Flood Map for Planning. They are based on the probability of flooding from rivers and the sea, and they do not account for the benefit of flood defences or for future climate change. The map was updated on 25 March 2025 using the new National Flood Risk Assessment (NaFRA2), and on 27 August 2025 the Environment Agency added a "Flood Zones plus climate change" layer showing how Zones 2 and 3 may expand under climate allowances. A site that is outside Zone 2 today can still sit inside the climate change extent.

Flood Zone 1: low probability

Land with less than a 0.1% (1 in 1,000) chance of river or sea flooding in any year. Most of England is in Flood Zone 1 and there are few flood-related planning restrictions.

All types of development are acceptable in Flood Zone 1 as far as flood zones go. You will not normally need a site-specific flood risk assessment (FRA), although one is required for sites of 1 hectare or more, on land with critical drainage problems, or on land that the Flood Map for Planning or a strategic flood risk assessment shows at risk from any source now or in future.

Flood Zone 2: medium probability

Land with between a 0.1% and 1% (1 in 1,000 to 1 in 100) annual chance of river flooding, or between 0.1% and 0.5% (1 in 1,000 to 1 in 200) of sea flooding. A site-specific FRA is required for all development. Only highly vulnerable development, such as basement dwellings, needs to pass the Exception Test. The Sequential Test may apply (see below).

Flood Zone 3: high probability

Land with a 1% (1 in 100) or greater annual chance of river flooding, or a 0.5% (1 in 200) or greater chance of sea flooding. It is divided into:

  • Flood Zone 3a: high probability. Homes and other "more vulnerable" uses need to pass both the Sequential Test and the Exception Test. Highly vulnerable development should be refused.
  • Flood Zone 3b: the functional floodplain, where water has to flow or be stored in a flood. Only water-compatible development, and essential infrastructure that passes the Exception Test, should be permitted. Councils identify it in their strategic flood risk assessments, with the Environment Agency.

The Sequential Test

The Sequential Test steers new development towards the areas with the lowest risk of flooding. It is set out in the National Planning Policy Framework (NPPF), whose flood chapter (policies F1 to F9) was rewritten in the version published on 17 August 2026.

For a planning application in Flood Zone 2 or 3, the council considers whether the development could go on a reasonably available site at lower risk. If it could, the application should normally be refused. The test does not apply to sites already allocated in the development plan and tested at plan-making stage, and it does not apply to householder development or to non-residential extensions under 250 square metres. If you are only extending your house, you are not asked to prove there is nowhere better to live.

The Exception Test

Where the Exception Test applies, the development must show that:

  1. It provides wider sustainability benefits to the community that outweigh the flood risk
  2. It will be safe for its lifetime, taking account of climate change, without increasing flood risk elsewhere and, where possible, reducing flood risk overall

Both parts must be met.

Flood risk assessments

A site-specific FRA is required for:

  • All development in Flood Zones 2 and 3
  • Development in Flood Zone 1 on sites of 1 hectare or more
  • Development in Flood Zone 1 on land with critical drainage problems, or land the Flood Map for Planning or a strategic flood risk assessment shows at risk from any source (including surface water) now or in future

An FRA is a technical report, usually prepared by a flood risk consultant or civil engineer. It assesses:

  • The risk of flooding from all sources: rivers, sea, surface water, groundwater, sewers and reservoirs
  • How the development will manage flood risk through its life
  • Whether it will increase flood risk elsewhere, for example through surface water runoff
  • Mitigation, such as raised floor levels, flood storage or sustainable drainage

What flood zones mean for property owners

Insurance

Properties in Flood Zone 3, and to some extent Flood Zone 2, may face higher premiums or difficulty getting cover. Flood Re, introduced in 2016, caps flood insurance costs for eligible homes, but only homes built before 1 January 2009 qualify. Newer homes in high-risk areas may struggle to get affordable cover.

Mortgages

Some lenders are cautious about homes in Flood Zone 3 and may want evidence the property can be insured. In extreme cases, a lender may decline.

Property value

Flood risk can affect what a property is worth, but the effect depends heavily on the site, its defences and its history. Ask your surveyor and insurer rather than relying on a general figure.

Extensions and alterations

If you extend or alter a property in Flood Zone 2 or 3, you need a flood risk assessment, but for a householder extension, or a non-domestic extension of up to 250 square metres, the Environment Agency's standing advice sets out what it must cover. It asks for finished floor levels at least 600 mm above the estimated flood level (sometimes 300 mm where the estimate is highly certain), or extra flood resistance and resilience measures where that is not possible. You may need to include flood mitigation measures such as:

  • Raising finished floor levels above the predicted flood level
  • Using flood-resilient construction materials and techniques
  • Fitting flood-proof barriers to doors and other openings
  • Placing electrical sockets and services above the predicted flood level

Surface water flooding

Flood zones only cover river and sea flooding. Surface water flooding, where heavy rain overwhelms drains and flows overland, is a separate risk that is not shown in the flood zones. Some land in Flood Zone 1 has significant surface water risk.

You can check surface water risk on the government's Check your long-term flood risk service.

Wales: the Flood Map for Planning and TAN15

Wales does not use the English flood zones. Since the revised Technical Advice Note 15 (TAN15) took effect on 31 March 2025, Natural Resources Wales's Flood Map for Planning has replaced the old Development Advice Map and its zones A, B, C1 and C2. The Welsh map has its own Flood Zone 2 and Flood Zone 3 for rivers and for the sea, plus surface water and small watercourses, and its zones include a climate change allowance. It also shows "defended zones" where flood defences meet a minimum standard of protection, though a defended zone is not automatically suitable for development. Flood assessments in Wales are Flood Consequences Assessments under TAN15, not English FRAs.

Scotland: flood likelihood, not flood zones

Scotland has no Flood Zone 2 or 3. The Scottish Environment Protection Agency (SEPA) publishes flood maps in three likelihood bands: high (about a 1 in 10 chance each year), medium (about 1 in 200) and low (about 1 in 1,000). Planning policy is National Planning Framework 4 (NPF4, policy 22 on flood risk and water management) and the local development plan, not the English NPPF. NPF4 treats land with an annual flood probability above 0.5%, including a climate change allowance, as at risk of flooding.

How to check flood risk

  1. Check a site free: check a site free includes a basic flood check for England, Wales and Scotland. The site report (£9.99, one-off) adds the detailed flood findings with their source, within 500 m of your pin, for 30 days. The report link never expires. It shows each nation in its own terms: Flood Zones in England, the Flood Map for Planning in Wales and SEPA likelihood in Scotland. In England the checker reads Flood Zones 2 and 3 from the Environment Agency Flood Map for Planning (March 2025 edition, revised May 2026). The Environment Agency map below is the official view to compare it with.
  2. The official English map: the Environment Agency's Flood Map for Planning covers England. In Wales use Natural Resources Wales; in Scotland use SEPA.
  3. Long-term risk: the Check your long-term flood risk service (England) covers surface water and reservoirs.

We show what we found, what came back clear, and where a source couldn't be checked. Some councils don't publish every dataset, so ask the council where it matters.

Summary

  • Flood Zone 1 is low risk with few restrictions; Zone 2 needs an FRA; Zone 3 can need both the Sequential and Exception Tests
  • Householder development is not subject to the Sequential Test in England
  • Flood zones cover river and sea flooding only, and ignore defences
  • Wales uses the TAN15 Flood Map for Planning, and Scotland uses SEPA's high, medium and low likelihood
  • Insurance, mortgage lending and value can all be affected

Sources

Buying a property?

Check the site before your solicitor orders searches.

Searches are usually ordered after your offer is accepted. Check a site free first for your council, conservation area status and a basic flood check. The site report (£9.99, one-off) adds everything else we can check within 500 m of your pin, for 30 days.

Check a site free →See a sample report

We show what we found, what came back clear, and where a source couldn’t be checked. Some councils don’t publish every dataset, so ask the council where it matters. Planning Constraints is a screening tool, not an official local authority search or professional advice.