Historical performance

There are 32 regulated companies in the water and sewerage sectors. Of these, 18 are regional monopolies that provide either water services, or both water and sewerage services. We report on the performance of these water companies using the information they publish each year.

Find out more about the information they must publish. Companies will publish their first annual reports under this framework in July 2016.

Historical performance dataset aligned with PR24 performance commitment definitions

The dataset provides Ofwat’s version of historical data for all PR24 performance commitments based on PR24 definitions up to 2024-25. The data is mostly based on data submitted by companies in their annual performance reports. However, adjustments have been made where necessary following the in-period determination process and review of company provided data on PR24 performance commitments.

PR24 Performance commitment definitions

Latest version – Historical performance trends for PR24 V6.0 (published 15 January 2026).

Long-term trend data

This long-term trend dataset is a compilation of performance data for several performance commitments going as far back as 1999-2000, where definitions have not changed significantly over time. Several sources of data have been stitched together including data from the PR24 datasets, water company performance report (WCPR) data, service delivery report data (SDR), June return data and data provided by companies through queries.

Past information on company performance

Until 2010-11, each company sent us detailed information about their performance each year. This annual data submission (or ‘June return’) was published to allow customers and stakeholders to understand each company’s performance. Under our risk-based approach to regulation, from 2011-12 onwards we stopped collecting the June return. And between 2011-12 and 2014-15 companies published key information about their performance each year.

Our company monitoring framework and annual performance reporting process applies from 2015-16.

Information published 2011-12 to 2014-15

We expected companies to publish the following information:

• key performance indicators (as often as they liked but at least once a year) in four areas:
  • customers
  • environmental impact
  • reliability and availability
  • financial
• a risk and compliance statement (once a year)
• regulatory accounts and accounting separation information (once a year)

Information collected until 2010-11

The information we used to collect was set out in the June return reporting requirements and definitions manual. We published revised reporting requirements each year.

The information required in the June return was divided into:

• Board overview
• key outputs
• bad debt
• vulnerable customers
• non-financial measures
• sewerage explanatory factors
• the regulatory accounts
• financial measures
• expenditure comparisons by purposes
• health and safety

Some of the information collected was considered to be commercially confidential. This was excluded from the public version of the return. Some companies also excised other information from their public June returns. Details of company excisions can be found in the individual companies’ confidentiality statements.

We did not collect information from Cholderton and District Water Company, as it is an exceptionally small company.

Elements of companies’ earlier data submissions are available on The National Archives at the links below.

• June return 2010
• June return 2009
• June return 2008
• June return 2007
• June return 2003-2006

Data from earlier years was not published on our website, but may be available by contacting us.