On 10 March 2026 the Competition and Markets Authority issued its provisional redeterminations on the PR24 water price control appeals. Five companies — Anglian Water, Northumbrian Water, South East Water, Southern Water and Wessex Water — had referred Ofwat's December 2024 final determinations to the CMA, arguing the bill increases allowed (averaging 36% over 2025-2030) were not enough. The CMA allowed an additional £556 million in revenue, roughly 21% of the £2.7 billion the appellants had requested. For non-household customers on these five networks, that translates to roughly a further 3% increase on top of the 24% increase already in flight under Ofwat's original determination, with the timing of pass-through depending on each retailer's annual price reset.
Why this is not a domestic-only story
Most of the press coverage of the 10 March 2026 decision focused on household bills — understandably, given the political salience. But the wholesale charges that flow through to non-household water bills are set by the same price control. A pub on the Southern Water network, a small manufacturer on Wessex, a care home on Anglian — all face the same wholesale uplift. Unlike the domestic side, there is no microbusiness-equivalent backstop or price-cap protection on the non-household side. The wholesale element resets with the price control; the retail element is set commercially by your retailer.
What does that look like in practice? On a typical SME water bill, somewhere between 80% and 90% of the charge is wholesale (charges set by the regional wholesaler under the PR24 price control) and 10-20% is retail (your retailer's margin, billing services, customer service). When wholesale charges go up by 24% across the price-control period, your bill goes up by around the same percentage — the retail layer cannot absorb it, because the retail margin in the non-household market is already thin. Our UK business water retailers ranking covers which retailers operate in which areas and how their margins compare.
Which appellant areas are affected, and which are not
Customers on Thames Water, United Utilities, Severn Trent, Yorkshire Water, South West Water, Affinity Water, SES Water, Bristol Water, Portsmouth Water, Hafren Dyfrdwy, and Welsh Water (Dŵr Cymru) networks are not directly affected by the CMA decision. They remain on the prices Ofwat set in the December 2024 final determination. Customers in the five appellant areas — Anglian, Northumbrian, South East, Southern, Wessex — face the additional 3% on top.
The CMA's reasoning, set out in its provisional report, accepted parts of the appellants' arguments on cost recovery and rejected others. The headline allowed extra of 21% of the appeal request was a partial win for the companies, not a vindication of their original numbers. The CMA's final report was due to follow the provisional report, with implementation by Ofwat shortly after. Until the final report and Ofwat's implementing decision, the precise pass-through for each customer is provisional. Once locked, the new rates flow through retailers' annual price reviews, normally aligned to April or to contract anniversaries.
What you can challenge, and what you cannot
You cannot challenge the wholesale element. That price is set by regulation. What you can challenge is everything else on the bill — and the everything-else is bigger than businesses usually realise. Three areas reward investigation. First, retroactive adjustments: under Ofwat's Customer Protection Code of Practice (CPCoP) section 9.3.1, retailers cannot recover charges older than 16 months for non-household customers. We cover this in detail in our water back-billing claims guide. Second, leakage and wastage: under the Wholesale Retail Code, retailers must investigate suspected leaks and apply leak allowances when confirmed. This is rarely done automatically. Third, meter accuracy: under the Water Industry Act and the WRC, customers can request meter testing, and inaccurate meters trigger refund obligations.
For larger non-household customers — manufacturing sites, hospitality groups, care home operators — switching retailer is also a real lever. The retail margin is small but not nothing, and retailers compete actively on service and on bundled services like water audits. The Open Water market data confirms that a meaningful share of non-household sites have not switched retailer since the market opened in April 2017, despite being free to do so. Our broader water cost review service walks through how to scope and run the comparison.
What to do if this affects you
- Within 14 days: confirm whether your site is on one of the five appellant networks (Anglian, Northumbrian, South East, Southern, Wessex). Your retailer can confirm.
- Within 30 days: pull the last 24 months of charges and identify the wholesale-vs-retail split. Retailers must provide this on request under the WRC.
- Before your next price review or contract anniversary: ask the retailer in writing how the CMA decision will affect your wholesale charges, and request a rate quote that holds for as long as possible.
- If your bills include any portion older than 16 months: challenge under CPCoP s.9.3.1. The text of the rule is short and the regulator's adjudication is consistent.
- If you suspect a leak or wastage event: insist the retailer raise an investigation under the WRC and apply any confirmed leak allowance retroactively.
- If a complaint stalls: escalate to the Consumer Council for Water (free) and, if unresolved, to the Water Redress Scheme (WATRS).
Frequently asked questions
Q: Will my bill go up by exactly 3%?
A: No — 3% is the average across appellant areas. Your specific increase depends on your wholesaler and on the mix of water-only vs water-and-wastewater services on your bill.
Q: When does the new wholesale rate apply?
A: Most retailers reset prices annually in April or on contract anniversaries. The CMA decision feeds into Ofwat's implementation, which retailers then pass through at the next reset.
Q: Can I switch retailer to escape the increase?
A: Switching retailer changes the retail layer (around 10-20% of the bill) but not the wholesale layer (around 80-90%). The wholesale element follows you regardless of retailer.
Q: Does the Water Reform Bill change any of this?
A: The Water Reform Bill, which we cover in our Water Reform Bill 2026 article, addresses long-term governance and structure of the water sector. It does not change the price control already in force.
Sources: GOV.UK, "Provisional redeterminations on water price controls issued", 10 March 2026 (CMA case ref Water PR24 Price Redeterminations); Ofwat PR24 Final Determinations, December 2024; Consumer Council for Water annual complaints data 2025; Wholesale Retail Code and CPCoP (current versions, Ofwat).