Is Thatcham in a flood risk zone?

River flooding

Locations at risk of river flooding are mapped on the Environment Agency’s website www.environment-agency.gov.uk.

Very few properties in Thatcham lie in the active floodplain of the River Kennet,

Surface water flooding

The flooding that occurred on 20 July 2007 was caused by surface water associated with a rainstorm calculated on a frequency of 1 in 169 years, i.e. an extremely rare occurrence. Much of the flooding followed the line of natural watercourses, that are mostly culverted under the town. Computer modelling to map surface water flood risk is currently being commissioned. This exercise will identify if parts of Thatcham are at significant risk of surface water flooding under different storm scenarios. For insurers, the risk considered ‘significant’ is a flood event occurring in 1 in 75 years or less. Properties that were not flooded on 20 July 2007 cannot be considered at significant risk of surface water flooding, on the basis they were not flooded during a 1 in 169 year event. It is also unlikely that many of the properties flooded in 2007 are at significant risk of flooding, using the insurance industry’s risk assessment (1 in 75 years).  However, the degree of risk for individual properties cannot be quantified until the computer modelling exercise has been completed.


The vast majority of properties that flooded in 2007 had not been flooded before. They were flooded due to an extreme weather event that was of an unprecedented scale. However, some insurance companies have substantially raised the excess payable for flooding on renewal of premiums. The National Flood Forum advises that substantial increases should be challenged by property owners, in cases where there is no prior history of flooding. The Association of British Insurers has produced a Statement of Principles on the Provision of Flood Insurance and property-holders should refer to this if they believe they are being unfairly treated by their insurers. The insurance industry has recently committed to continue to provide flood insurance to the vast majority of UK customers, including those whose properties have been flooded before.