The Water Industry (Specified Infrastructure Projects) (English Undertakers) Regulations 2013 (the SIP Regulations/SIPR) allow the Secretary of State or Ofwat to specify as ‘specified infrastructure projects’ projects that must be put out for competitive tender by a water company for delivery by a third-party infrastructure provider (IP). The Regulations relate to water companies whose appointment areas are wholly or mainly in England. SIPR is therefore currently only available for use in England.
The Regulations were made with the purpose of allowing that third party infrastructure providers may finance, design, build, maintain and operate large new infrastructure, in circumstances where the relevant water companies would be unable to do so without a detrimental effect on the rest of their businesses.
The Regulations require Ofwat to issue guidance on the criteria for specifying an infrastructure project or in determining whether to vary or revoke such a specification notice. Ofwat published such guidance in May 2015 and published updated guidance in May 2025, which took account of changes that have taken place in the regulated water sector since 2015 to ensure that the guidance remained fit for purpose.
To date, only one project has been delivered under SIPR – the Thames Tideway Tunnel. At PR24, 3 projects indicated a preference for delivery under SIPR, however none of these projects have been specified at this stage. White Horse Reservoir is currently in the process of seeking specification, with Ofwat’s draft reason for specification having been published for consultation in April 2026.
We are working closely with Government to support growth, including working with Defra to amend the SIP regulations in England to enable more flexibility in the use of SIPR, allowing major water projects to be delivered more quickly and with better value to billpayers. We are also working with Defra on possible future legislative needs and await recommendations from the independent commission into the water sector regulatory system, led by Sir Jon Cunliffe.
In May 2026, we issued Consultation on draft guidance for water companies delivering projects under the Specified Infrastructure Projects Regulations, which sets out our regulatory and commercial expectations where water companies are developing projects to be delivered under SIPR. Final guidance will be issued in late 2026.