Mental health costs of flooding

Including the impact of floods on people’s mental health for the first time.

A method for monetising the mental health costs of flooding 

Christophe Viavattene 1, Sally Priest 1, Jacqui Cotton 2 and Carolann Simmonds 2

1 Faculty of Science and Technology, Middlesex University, United Kingdom

The Environment Agency and risk management authorities routinely include the mental health impacts of flooding in investment decisions following research published in 2021 A method for monetising the mental health costs of flooding.

Prior to this research, investment decisions focussed on the economic damages to homes, businesses and infrastructure. Although authorities knew that those affected by floods suffered with mental health conditions, there was insufficient robust data available to develop a new method. However, in 2017, Public Health England published the results of a national study on the impacts of flooding on mental health and well-being.

This study showed that people whose homes had been flooded suffered high levels of probable depression, anxiety and post-traumatic stress disorder. The study provided the figures needed to look at the economic damages for the first time. Subsequent studies showed these impacts could last for at least 2 years after the flood.

The Environment Agency project took this new data and used it to calculate the costs of the mental health impacts. These costs include treatment and medication, and loss of employment or earnings due to time off work. The project worked out the value to be £1,878 per adult per flood for shallow floods (less than 30cm of water in a home) to up to £4,136 per adult per flood for deeper, more severe floods (when water is over 1 metre deep). Deeper floods result in more possessions being lost and people being away from their homes for longer during repairs. This increases the impact on those affected, and thus increases the cost.