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Our leakage performance

Headlines for March 2021 (published April 2021)

  • 20% increase in average leaks fixed each week compared to February: We completed 6,882 leak repairs in March, the equivalent of 1,376 leaks on average each week. This is 20% more each week on average than during February, and we prevented the equivalent of 44 Ml/d of leakage through leak repairs.
  • Monthly leakage for March was 655 Ml/d: That’s 80 Ml/d above our internal target, however, average leakage levels for March were 77 Ml/d below February levels and we’re 14Ml/d closer to our plan compared to February.
  • Covid-19 restrictions from earlier in the year and the colder than average weather in February have impacted our year-to-date performance: Our annual average leakage after March is 24 Ml/d above our internal target for the April 2020 to March 2021 period.
  • Our final leakage position for 2020-21 will not be available until after the completion of our year-end assurance and audit process. The final position will take into account any revisions required to the starting baseline position together with factors such as assessments for growth in population, property numbers and Covid-19 impacts on night usage. For the purposes of this report, we have maintained consistency with the numbers reported last year until our final leakage performance is determined. Our leakage performance for the year will be published in our Annual Report in July 2021.

A Thames Water van driving through London.

The spike in leakage and bursts, due to January and February’s colder than average weather, continued to have a knock-on impact on our leakage levels in March. We also continued to experience colder than average weather in March, with temperatures being 0.3oC below the long-term average. Temperatures were 0.6oC below the long-term average for the January to March period.

In the coldest week of February, when water temperatures were almost 1.7oC colder than average, we saw an increase of 128 Ml/d in leakage. We worked quickly to reduce leakage back down to pre-cold snap levels, however this extra work affected our existing leakage reduction plans. As we were unable to complete enough planned work during February, we increased the amount of work we did to fix leaks in March, leading to a 20% increase in the number of leaks fixed compared to February.

We’re continuing to take lots of steps to reduce our leakage, including improving the way we talk to our customers about how they can protect their own pipes and innovating to create a smarter network. We know we need to get to a position where we’re not affected by weather shocks, and we’re implementing a plan to transform the way we run our water network to improve our resilience and operational performance. We’re also laying the groundwork for a longer term, ground-breaking new project to replumb London and parts of the Thames Valley, so we can provide a water service that is fit for the future.

Going into 2021/22, we’ve taken account of our current leakage position, and the challenges we’ve faced during the year, to ensure we develop a robust plan with increased activity to meet our leakage performance targets.


The information provided is, to the best of our knowledge, accurate, but may be subject to change from time to time. The information does not represent formal annual regulatory reporting.

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