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Our leakage performance

All leakage figures quoted in this report are calculated in line with those in previous reports and do not yet reflect the final year end numbers. This will be updated in next month’s leakage report after we publish our Annual Performance Report.

Headlines for May 2021 (published June 2021)

This is our second monthly leakage report for 2021/22. It explains our performance for May 2021.

  • Monthly leakage for May was 592 Ml/d
  • Leakage has reduced week on week throughout May, with the level of leakage at the end of May 53 Ml/d lower than at the end of April
  • We completed more leak repairs than planned during May: We completed 4,925 leak repairs in May – the equivalent of 1,231 leaks on average every week and a 26% improvement on our average weekly repairs in May last year.

We’re aiming to achieve a substantial reduction in our base leakage level this year, and we’re working towards a 20% reduction over the five-year regulatory period.

We’ll publish our final leakage position for 2020/21 in our Annual Performance Report on 6 July, after we’ve completed our year-end audit process. This includes readjustments for the estimates that are made throughout the year, which include assessments for growth in population and property numbers.

Our final position for 2020/21 will take into account any revisions as a result of the year end assurance and ‘true-up’ activities and will re-set the baseline position for this price review period. The new baseline position will also reflect the new leakage reporting methodology for the year and be reflected in our targets for the period. Our forecasts will also be revised.

A Thames Water engineer reading data from a handheld machine


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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