Risk of Flooding from Surface Water (RoFSW) map is an assessment of where surface water flooding may occur when rainwater does not drain away through the normal drainage systems or soak into the ground, but lies on or flows over the ground instead. It includes information about flooding extents and depths. It is produced using national scale modelling and enhanced with compatible, locally produced modelling from lead local flood authorities (LLFAs).
RoFSW is a probabilistic product, meaning that it shows the overall risk, rather than the risk associated with a specific event or scenario. In externally published versions of this dataset, risk is displayed as one of three likelihood bandings:
High - greater than or equal to 3.3% chance in any given year (1 in 30)
Medium - less than 3.3% (1 in 30) but greater than or equal to 1% (1 in 100) chance in any given year
Low - less than 1% (1 in 100) chance in any given year
NB. This is a complex dataset, with preview available only on certain zoom levels. The Web Mapping service has been set to 1:50 000 in the attribute. The services are set to be visible from the 1:50 000 scale range. There may be some variation, since end client software may interpret the request differently.
Attribution statement: © Environment Agency copyright and/or database right 2025. All rights reserved.