5m UK and Republic of Ireland Flood Map

Since 1998, the UK has experienced seven of the ten wettest years on record. JBA's modelling estimates that one in four UK properties are at risk to flooding, with annual damages from flood estimated between £500 million and £1 billion each year, and over 45,000 homes are at risk to flood in Ireland.

This is likely to increase under a changing climate. Comprehensive flood data is therefore key to managing the risk both now and in the future. 

As a result, over 13 years since we first released our data, we remain committed to the continued development of our 5m UK and Ireland Flood Map. Now in its eleventh generation, our mapping was the first to offer national coverage for all major flood types at 5m resolution, empowering the re/insurance, financial, NGO, charitable and public sectors in their flood risk assessment and management. 

2021 update

We offer an annual update to our mapping in response to client feedback and new data availability. We also consider new methodologies and check areas where new methodology might bring the greatest benefit to both data and efficiency. 

The 2021 release includes elements of all these with the adoption of updated methodologies as well as the use of new elevation data to upgrade surface water(pluvial) and undefended river(fluvial) flooding for four significant catchments in UK, including parts of London and Birmingham, and six catchments in the Republic of Ireland. The update also includes new defended data to reflect the addition of new defence schemes (including demountable and temporary defences) and an improved system of delivering ‘vertical street’ postcode data.

Following the updates to our coastal mapping in 2020 which was the culmination of a complete remapping of England and Wales coastlines, this year we have updated coastal areas in Republic of Ireland due to the availability of new elevation data.

Republic of Ireland defence detail has also been updated to accommodate new additional river defence schemes in Galway, Limerick, Ennis and Dublin.

Other defence improvements have also been addressed in certain areas of UK to include both new defence schemes and the latest Environment Agency data. Additionally, demountable and temporary defences have been added for a more realistic reflection of flood risk. Defended view is optional depending on the user’s view of risk.

And finally, the 2021 postcode database will present an easier, more simplified view of the postcodes of buildings with multiple residences. In this update a building of multiple residences is presented as a single building footprint. This will demonstrate a more appropriate view of flood hazard for the buildings in the postcode and avoid the need for an additional look-up table.


Comprehensive flood modelling

Our flood data can be used by re/insurers, mortgage providers, banks, asset managers and other investment organisations to effectively assess the extent and severity of flooding, for improved decision-making across risk selection, underwriting, pricing, portfolio optimisation and funding and investment opportunities. The data can also be used by public bodies for land use planning, disaster preparedness and more.

We use bespoke methods for each flood type to account for their unique hydrological characteristics, with an option to view each flood type separately or in combination for a more comprehensive insight into which flood type may be the driver of losses and what the potential claims costs may be.

Our mapping captures all major rivers and smaller streams in the UK and Ireland at high-resolution 5m grids – key for a highly localised peril where one property might be flooded and the neighbour spared – and specific modelling is undertaken for the Thames Estuary to understand a worse-case scenario on the Thames river and surrounding areas. This high-resolution approach allows for more competitive pricing through better differentiation between properties at risk for the major flood types.

The mapping is complemented by our Defended Areas datasets, delineating areas that may be protected by defences despite being flooded in our maps, to enable clients to make business decisions according to their own risk appetite by incorporating all, some or none of the defences in their risk assessment.

The mapping is accompanied by a range of associated data, including simple flood risk scores and colour-coded flood ratings at property level, as well our financial metrics at both location and portfolio level from our Pricing Data and UK probabilistic flood model.

The mapping can also be used alongside our range of climate change data to understand potential changes in flood risk across the UK.

We're committed to ensuring our clients can access our data in a way that suits them. For easy integration into existing systems, our UK Flood Map is platform agnostic and available:

  • In-house directly from JBA
  • Via our wide range of resellers
  • As part of a JBA consultancy service to help identify exposure hotspots, run per-risk flood assessments and manage accumulations.

For more information on any of our UK data, please get in touch. We also have 5m flood maps available for the US and Continental Europe, as well as 30m flood mapping globally.

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Flood Services

Catastrophe Models

Our suite of high-resolution catastrophe models and event sets utilise the latest science to assess the potential severity and frequency of flood losses to global property portfolios.

Maps And Analytics

Our market-leading high-resolution global flood maps and analytics enable users to understand and manage their flood risk, using the latest research and innovation.


We work on a bespoke basis to offer unique solutions to your flood risk problems, from single site assessments and flood defence design to portfolio optimisation and tailored model builds, working with you to meet your needs.

Event Response

Our specialist event response team monitors global conditions to provide expert commentary, guidance and data for major flood events, allowing you to understand the impact on your business.