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London flooding response

In July 2021, London was hit twice by extreme rainfall, which led to widespread flooding. At its heaviest, a month’s rain fell on some parts of the capital in just one hour.

This tested our sewers and local authorities' drains and gullies. The speed, severity, and scale of the rainfall was beyond the limits they were designed to cope with. This led to the flooding of more than 2,000 properties. 

We sympathise with everyone impacted by flooding. View more information on different types of flooding and who can help.

Forecasts suggest severe rainfall will become more common due to climate change. We've carried out two reviews to see what actions we can take to reduce the impact of such storms. 

London skyline and River Thames

Thames Water review

We know the service we provided our customers with following the storms was not good enough. Many people were unable to contact us and our teams were slow to get to some of the worst hit areas.

So, we carried out an internal review to examine the actions we took before, during and after the storms. This helped us to identify what we could have done better so we can develop these actions for next time.

Internal review downloads

London flood review

We wanted to find out if our sewer network may have worsened the impact of the extreme weather. This would help us to understand why the flooding in July 2021 was so severe.  

For a transparent and impartial process, we commissioned an independent assessment. This was carried out by a group of experts and chaired by Mike Woolgar.

The independent report had four core objectives:

  1. Research, understand and report on the “what, when, why and how” of the two July storms
  2. Examine the flooding mechanisms. Consider the performance of drainage systems against design standards. Focus on Counters Creek and Maida Vale Flood Alleviation Schemes
  3. Consider changes to existing and planned drainage system works, operations or policies. Determine if they could've alleviated flooding and make London resilient to future storms
  4. Be as evidence-based as possible

The review is now complete and will help us put a plan in place for future incidents. 

Independent review downloads

Counters Creek performance commitment report

Ofwat asked us to report on performance within the Counters Creek catchment. This includes the risk of flooding and level of resilience.

Read the full Ofwat requirements for this report. The requirements can be found in section 1.2.37 (pg 153) of the Ofwat PC commitments.

Counters Creek downloads