PN: 37/21 Thames Water will pay over £11 million to business customers and water retailers after data errors


Ofwat has finalised its decision which will see Thames Water pay over £11 million to 13,800 business customers and water retailers for errors in its data which led to customers being billed the wrong amount.

In addition to the financial package, Thames Water has proposed a series of undertakings which, among others, include strengthening its internal processes and controls relating to how it handles market data and complaints.

Having considered all the responses to the proposed decision, Ofwat has accepted the original undertakings and financial package put forward by Thames Water, and in light of this has issued a nominal penalty of £1 on Thames Water.

Emma Kelso, Senior Director at Ofwat said:

‘Our investigation uncovered a multitude of errors with the way Thames Water handled its data before and after the business retail market opened. It failed to act, even when it became apparent from its own risk assessments or from complaints it received that there were concerns over the accuracy of its data. It should have done more to investigate and correct its errors. It’s unfair that customers and others in the market have suffered as a result.

It is right that Thames Water will now address this. Data quality is vital to a successful business retail market and the benefits that it can bring for customers. Water companies and retailers have legal obligations they must fulfil in ensuring the data they are responsible for is complete and accurate. The package and undertakings are a fair outcome for the business customers and water retailers who were badly let down by Thames Water.

This case shows the importance of wholesalers being on top of their customer and operational data and is relevant across the whole of their businesses. The importance and value of data is growing, and company boards must have a strong focus on this when providing their assurances that they are able to effectively provide their regulated services.’


Notes to editors

  1. Thames Water – Final decision and penalty notice
  2. Thames Water – proposed decision
  3. Case summary
  4. Payments will be completed within one month of issuance by Ofwat of its final penalty notice.
  5. Implementation of recommended actions to be completed by the end of 2022. These are subject to review, and agreed amendment where necessary, once the external audit has been completed and its findings considered by the Executive.