Managing flood risk in London

Our focus is strengthening borough capacity in this area. 

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Surface Water Flooding

Surface water flooding is the main flooding risk to London, as noted in London’s Risk Register. It occurs when the drainage system is overwhelmed, and rain cannot get into local drains, sewers, or watercourses. It can be caused by intense rainfall and/or blockages within the system. It is difficult to predict when and where surface water flooding will occur due to uncertainties in timing, location and intensity.

See full Surface Water Update from London Councils' TEC Committee. 


Every London borough is responsible for flooding as a Lead Local Flood Authority (LLFA). They work in partnership with the Environment Agency, Thames Water and other stakeholders to manage flood risk. LLFAs must identify the flood risks in their area, what interventions could help to mitigate those risks and apply for funding for interventions where there is a good business case. We are working to strengthen these partnerships.  

London Councils appoints seven members to the Thames Regional Flood and Coastal Committee. The Chair of the London Councils Transport and Environment Committee and the Chair of the Thames RFCC has agreed joint working arrangements. Through this committee we have secured a team of Thames Flood Advisers who provide additional capacity to the London boroughs as needed on flood risk management capital projects. 

Sustainable drainage

Both the Mayor's Transport Strategy and London Environment Strategy identify the risks to London from surface water and strengthen Mayoral policy relating to encouraging sustainable drainage. TfL has published its guide to incorporating SUDS in roads and public realm, called 'SUDS in London - a Guide'. 

The GLA is mapping SUDS across London. Boroughs are encouraged to submit sites for inclusion to the GLA. The GLA has also mapped London's street trees

Map of London showing sites of sustainable drainage