As the most complete and up-to-date flood data set for the United Kingdom, UKFloodMap4™ provides accurate and easy-to-understand flood risk information for individual properties across the country.

At a Glance

  • Detailed visualisations of potential flood risks across 100% of the UK
  • Models fluvial (rivers), tidal and pluvial (flash flooding) risks
  • Flood depth and velocity information for individual properties
  • Range of return periods
  • Hydrological and 2D hydraulic modelling
  • Integrated flow rate and rainfall data
  • Updated annually with all updates clearly communicated
  • Regularly validated and calibrated using actual flood events in the UK
  • Models 25% more rivers than any other UK flood model

Our flood maps are used around the world by insurers, government agencies, property developers and emergency response services to visualise, assess and understand potential flood risk.

flood outline
UK Floodmap4 flood outline (in blue) of the River Wye, UK

Wherever possible, UKFloodMap4 uses LiDAR data, which is vertically accurate to ±15cm. It also incorporates the most up-to-date river flow and rainfall data available from CEH, has a range of return periods, and covers all the main sources of flooding, including rivers, tidal and surface water.

Easy to integrate as flood maps or flood risk datasets

With UKFloodMap4 you can quickly present flood risk scenarios to customers, brokers or underwriting teams visually. The flood maps can be supplied as PDFs. or delivered as GIS (Geographic Information Systems) layers or flat files that can be integrated into online risk checking services or GIS-compatible systems (including LexisNexis, SpatialKey, Touchstone and ESRI).

As an Ordnance Survey partner we can license you for the OS AddressBase products too.

We can adapt to your challenges

Our team will advise you on how you can get the most from the data, and can support you with the integration. By using our knowledge of business processes, predictive analytics and flood risk, we can help you make best use of our data so that it adds value to your business.

Adds to your existing flood risk data

Even if you’ve already got a source of flood data, our specialist flood mapping data layers can support your flood risk strategy by giving you a more accurate and complete view of flood perils, right down to individual building level. It’s also used to assist in compliance and meeting best practice guidelines, such as compliance with Solvency II in the insurance industry.

Flexible licensing

UKFloodMap4 isn’t just for large organisations. To make it more accessible, the licensing options are very flexible: you can choose to have only a single flood source (eg surface water/flash flooding) or limit your set to a single city, county or region. We can also discuss how you can use it across your organisation, rather than just in siloed business processes.


  • Visualisations of potential flood risks make it easy to identify potential flooding issues
  • Helps insurers, government agencies, property developers and emergency response services make better decisions around flood risk
  • Assists in planning best responses to floods
  • Makes it easier to optimise pricing and improve loss ratios
  • Delivers more confidence in your portfolio management
  • Allows you to quickly assess new underwriting opportunities

Click for the technical details

Our flood sources:


  • Fluvial (river)
  • Tidal (sea/estuary/coastal)
  • Pluvial (flash/surface water)


  • Flood defence breaches
  • Dam breaches
  • Groundwater

Layers available

  • Depths: maximum depth experienced during flood, in metres
  • Velocities: maximum velocity experienced during flood, in metres per second

Horizontal grid resolution



EA LiDAR (nominal vertical accuracy ±0.15m)


National best practice

Modelled return periods

30 to 1,000 years


  • Full shallow water wave 2D modelling using Flowroute-i™ which allows for complex floodplain dynamics
  • Spatially variable land use (eg roughness/infiltration)
  • Building-level precision

Delivery formats

  • PDF maps
  • GIS layers ie shapefiles or raster (floating-point/classified). The data can be integrated with most GIS-compatible systems and third-party underwriting platforms, including LexisNexis, SpatialKey, Touchstone and ESRI.
  • Flat files to integrate with your systems or online risk-checking services
  • We can also supply appended to OS AddressBase products.

Update frequency



  • Flexible Licensing depending on requirements
  • Transactional (ie ‘per hit’) and territorial pricing (eg South of England only) options also available

“This data has provided us with a step-change in the way that we underwrite flood risk in the UK. Visualisation and analysis of flood risk at the individual address level is now a much easier, quicker, and more precise process for us.”

Chubb Insurance Company of Europe

We’ve invested five person-years into detailed, manual GIS processing to make UKFloodMap4™ as precise as possible.

Mark Nunns

Get in Touch

To get a quote or to discuss what you need, contact Mark Nunns

Call me on 0203 857 8543   or Email at

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