On 19 December 2024, Ofwat published its final decisions on price controls and what water companies in England and Wales should deliver for customers and the environment in 2025-2030.
The 2024 price review final determinations will see a quadrupling of new investment in the water sector over the next five years. This will provide companies with the funding needed to transform their performance, ensure supplies for future generations and deliver cleaner rivers and seas.
As part of the price review process, water companies had until 18 February 2025 to request an appeal of our decisions to the Competition and Markets Authority (CMA).
We announced that six companies requested a reference of our decision to the CMA.
- Anglian Water
- Northumbrian Water
- South East Water
- Southern Water
- Thames Water (reference to the CMA currently deferred)
- Wessex Water
Final Determinations
On 10 March 2026, the CMA submitted its final determinations report to Ofwat and on 26 March 2026, the CMA published its full final determinations report on this case page Water PR24 price redeterminations – GOV.UK.
On 23 April 2026, Ofwat republished the underlying models related to the PR24 redeterminations. These models set out the CMA’s approach to calculating allowed revenues and other price control elements.
CMA FD – Enhancement Aggregator
CMA FD – Opex capex split
CMA FD – Base costs aggregator model
CMA FD – Financial model – Anglian Water
CMA FD – Financial model – Northumbrian Water
CMA FD – Financial model – South East Water
CMA FD – Financial model – Southern Water (excluding DM)
CMA FD – Financial model – Southern Water (including DM)
CMA FD- Financial model – Wessex Water
The following models merge the CMA final determination and Ofwat’s Blind Year final determinations.
Base costs aggregator model (CMA FD and Ofwat Blind Year)
Base costs residential retail model 3 (CMA FD and Ofwat Blind Year)
Enhancement aggregator model (CMA FD and Ofwat Blind Year)
Opex capex split (CMA FD and Ofwat Blind Year)
21 October update
Thames Water has requested a further deferral of its 2024 Price Review final determination reference to the Competition and Markets Authority (CMA). Given the ongoing discussions with the company’s creditors, Ofwat has agreed to this request and informed the CMA. Thames Water and Ofwat agree that at this point in the review process there is no benefit in setting a definitive expected end date for the deferral decision.
Provisional Determinations
On 9 October the CMA published their provisional determinations. These are open for consultation until 6 November 2025.
2 October update
On 2 October, Ofwat shared with the CMA 10 updated models and error corrections.
Datasets
Base costs – Wholesale Water
Phosphorus removal enhancement
Supply interconnectors
Wastewater network plus
Phosphorus removal base cost adjustment
Updated error corrections
Enhancement aggregator
Opex capex split
Delivery mechanism allowances
Base costs aggregator
Meter renewals cost adjustment
Approach and prioritisation
We responded to the CMA’s request for views on their proposed approach and prioritisation for the PR24 redeterminations.
Response to disputing companies’ letters on each other’s statements of case
On 14 May we provided the CMA with our response to the disputing companies’ comments on each other’s statements of case. Those responses were published by the CMA on 1 May.
Response to disputing companies’ statements of case
PR24 redeterminations correction log
On 29 April we submitted our response to the disputing companies’ statements of case to the CMA:
- PR24 redeterminations – overview of our response to the statements of case
PR24 redeterminations – expenditure allowances – common issues (updated 22 May 2025)
PR24 redeterminations – outcomes – common issues
PR24 redeterminations – risk and return – common issues (updated 22 May 2025)
PR24 redeterminations – response to Anglian Water’s statement of case
PR24 redeterminations – response to Northumbrian Water’s statement of case
PR24 redeterminations – response to Southern Water’s statement of case
PR24 redeterminations – response to Wessex Water’s statement of case
PR24 redeterminations – response to South East Water’s statement of case
PR24 redeterminations – expenditure allowances – cost adjustment claims
PR24 redeterminations – expenditure allowances – addressing asset health
18 July update
Thames Water has requested a further deferral of its 2024 Price Review final determination reference to the Competition and Markets Authority (CMA).
Given our previously-stated view that the final determination is in the best interests of customers and the environment, Ofwat has agreed to this request and informed the CMA.
The company, its senior creditors and Ofwat have been engaged in constructive discussions in relation to the delivery of a market-led solution for the recapitalisation of the company, including through an equity raise, without the need for a CMA reference.
This further deferral of the reference until 22 October 2025 reflects the company view that allowing these discussions to continue in the coming weeks could result in steps that unlock the market-led solution, and Ofwat agrees that it is appropriate to continue the deferral in the circumstances.
8 April update
We have agreed to a request from the CMA for an extension of up to six months for the redeterminations to be completed. The CMA has published a timeline for the redeterminations.
18 March update
Ofwat has today formally referred the requests from five companies for a redetermination of their PR24 Final Determination to the CMA with an introductory submission letter. This commences the six-month period which the CMA has to consider appeals (subject to any request for an extension).
Thames Water requested a reference to the CMA last month, but has since asked for the formal reference to the CMA to be deferred for a period of up to 18 weeks. Following discussion with the CMA, and given our view that the final determination is in the best interests of customers and the environment, Ofwat has agreed to this request.
How does the CMA conduct the appeal process?
While we usually refer to these as ‘appeals’, that’s potentially misleading.
The CMA undertakes a full redetermination of Ofwat’s decision; it is not limited to assessing the specific issues raised by companies, the CMA has set out its approach in the CMA’s rules and guidance on water references.
The CMA will be providing information and updates on the progress of its work.
How long does the process take?
The initial period the process was scheduled to take was six months; however, the CMA can ask for one extension of up to a further six months. The CMA requested an extension given the nature and scale of the work involved in assessing the price controls for the five water companies and the associated procedural complexity, and Ofwat has agreed the request. The CMA therefore now has until 17 March 2026 to complete its report on the references, although it may do so sooner.
What impact will the appeal process have on water bills for customers of the companies who appeal?
Ofwat’s final determinations will come into effect from 1 April 2025 for all companies.
Bills for 2025-26 are therefore based on the price controls that Ofwat has set. If a company’s appeal leads to a change in its price controls then this will be reflected in bills in subsequent years.
If the CMA makes changes to Ofwat’s decisions will those changes apply to all companies?
No, any changes which the CMA makes will be specific to the companies that have appealed.