Partnering with GeoSmart, we can provide the most precise groundwater flooding dataset available in Britain today. This offers insurers, developers and property asset managers an even more comprehensive overview of flood risk.

At a Glance

  • Covers 100% of properties in Great Britain
  • 5m resolution allows for risk assessment at property level
  • Classifies risk as negligible, low, medium or high (1.5% of properties categorised as high)
  • Identifies areas within a property that may be at risk
  • Considers all aquifer types and permeable superficial deposits driven by overflowing rivers and high tides
  • Focuses on risk rather than susceptibility to provide a less conservative overview
Above is an example of a GW5 groundwater flood risk map of Hemel Hempstead. The advanced resolution is achieved using a 5m horizontal grid resolution which clearly identifies the individual properties at risk. The GW5 data provides information on different groundwater flood risk classification zones as seen by the colouration on the map.

Groundwater flooding is often overlooked when it comes to assessing flood risk. That’s even though it causes two to four times more damage to property than surface flooding events. It may occur far from traditional sources of flooding. It can take up to 30 days to appear after a surface water flooding event or it can often last much longer. All these factors make groundwater flooding harder to predict and more difficult to manage.

Refines your existing view of flood risk

By integrating GeoSmart’s Groundwater Flood Risk Map (GW5) into your flood risk data portfolio you can get a more detailed understanding of flood risk from all sources down to property level.

GW5 corresponds to Ambiental’s flood risk model (UKFloodMap4™). It does this in terms of resolution, precision modelling, quality, and a commitment to continually updating the data against actual groundwater flood events.

The highest resolution groundwater flood risk data available

GW5 shows groundwater risk at 5m resolution. Combining comprehensive data on geology, permeability and historic groundwater levels, it gives you unique insight into the actual risk of groundwater flooding, rather than just susceptibility.

Flexible licensing

GeoSmart GW5 is available with highly flexible licensing options, including regional scale pricing. It can be licensed on its own or integrated with FloodScore™ or UKFloodMap4.

Test GeoSmart GW5 data for yourself

Contact us for a free sample of GeoSmart GW5 data to test against your existing data sources.


  • Increase the precision of your flood risk management
  • Be more confident in your portfolio management and ceding decisions
  • Optimise pricing and reduce loss ratios
  • Help with Solvency 2 compliance

Click to view the technical details


Great Britain

Modelled return periods

1 in 100 years

Horizontal grid resolution


Topography input data

Environment Agency LiDAR and Ordnance Survey Terrain 50 (5m DTM)

Update frequency

Annual/after major events


Regularly validated and calibrated against actual flood events in Britain

Delivery formats

  • GIS layers: shapefiles or raster (floating point/classified/average annual loss)
  • Integrated with all GIS-compatible systems and third-party underwriting platforms including Experian, LexisNexis, Spatial Key and Touchstone
  • Appended to Ordnance Survey AddressBase® property level database
  • Flat file to integrate within customers’ systems
  • Physical/PDF maps
  • Through FloodScore™, Ambiental’s online flood risk assessment platform


  • Flexible licensing depending on requirements
  • Regional scale pricing also available eg South of England
  • Annual subscription and transactional ‘per hit’ pricing models available

The most precise groundwater flood risk dataset available in Britain.

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 [email protected]

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