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Around 90% of your water and wastewater bill is made up of Wholesale charges. These aren’t set by Castle Water, they’re determined by the Wholesaler in your region and approved by the regulator, Ofwat. That means you’ll pay the same Wholesale charges, no matter who your retailer is.
Wholesalers review their pricing every year. You can check the latest 2025/26 wholesale tariffs on your Wholesaler’s website, or by exploring our Scheme of Charges.
From 1 April 2025, updated charges will come into effect. As wholesale rates change, we update our pricing too. At Castle Water, we’re always transparent, so you’ll see a clear breakdown of both Wholesale and Retail charges.
Most customers will see their bills go up this year. That’s down to several factors: the latest industry-wide pricing review, changes made by regional Wholesalers, and revised guidance from Ofwat on Retail charges.
If you’re unsure which tariff you’re on, check your most recent bill, or just give us a call. We’re always here to help.
With business water rates increasing in April 2025, it’s important to understand how your region is affected. You can view the expected changes by Wholesaler below:
| Region | 2024-25 rate | 2025-26 rate | Percentage increase |
|---|---|---|---|
| Anglian Water | £527 | £626 | 19% |
| Welsh Water (Dŵr Cymru) | £503 | £639 | 27% |
| Hafren Dyfrdwy | £447 | £590 | 32% |
| Northumbrian Water | £426 | £506 | 19% |
| Severn Trent Water | £457 | £556 | 22% |
| South West Water | £520 | £686 | 32% |
| Southern Water | £478 | £703 | 47% |
| Thames Water | £488 | £639 | 31% |
| United Utilities | £486 | £598 | 23% |
| Wessex | £556 | £669 | 20% |
| Yorkshire | £467 | £602 | 29% |
| Region | 2024-25 rate | 2025-26 rate | Percentage increase |
|---|---|---|---|
| Affinity Water (central region) | £192 | £235 | 23% |
| Affinity Water (east region) | £225 | £278 | 24% |
| Affinity Water (south east region) | £249 | £291 | 17% |
| Bournemouth Water | £144 | £191 | 32% |
| Bristol Water | £226 | £234 | 4% |
| Essex and Suffolk Water | £286 | £318 | 11% |
| Portsmouth Water | £120 | £150 | 25% |
| South East Water | £245 | £294 | 20% |
| South Staffs Water (Cambridge region) | £163 | £203 | 24% |
| South Staffs Water (South Staffs region) | £178 | £224 | 26% |
| Sutton and East Surrey (SES) Water | £254 | £249 | -2% |
We know times are tough. Even small increases in costs can add pressure. If your business is struggling to manage bills, don’t wait to get in touch with us. The earlier we speak, the more we can do to help.
