Groundwater flooding

Groundwater flooding is the result of a slow process with groundwater levels rising over periods of days, weeks and months of extended rainfall resulting in water emerging trough the ground. Although it can appear to be localised it is the result of groundwater conditions across a wide aquifer. It can be difficult to prevent or mitigate against as it comes from below the ground.  It can also be slow to recede as groundwater levels drop gradually.

Monitoring groundwater levels

The Environment Agency (EA) monitors groundwater levels in areas that have historically experienced groundwater flooding, including parts of Croydon. Groundwater flooding is more likely to occur in southern parts of the borough where the predominant geology is chalk, although groundwater flooding may also occur in northern locations. Borough-wide mapping of groundwater flooding is available in Appendix E of the Local Flood Risk Management Strategy. 

The EA also provides a groundwater alert and warning service. For more information and the most up to date groundwater situation visit the Environmental Agency website.

See our Flooding, who is responsible page for information on how best to prepare your property for flooding.

More information on groundwater flooding can be found on the Project Groundwater website.
 

Report groundwater flooding

Due to the nature of groundwater flooding it can be difficult to identify the source and resolve the problem. If you are experiencing groundwater flooding, please follow these steps:

• Try to identify the source of the flood. This may be on yours or a neighbouring property. If on a neighbouring property, please notify the property owner and ask them to resolve the issue. 
• Report the issue to your clean water supplier: Thames Water or SES Water for a sample to be taken as the source may be a supply pipe.
• Report the issue to us as the Lead Local Flood Authority (LLFA). This will help us better understand flood risk across the borough.