From 1 April 2026, businesses across the UK will see an increase in water charges. Wholesalers revise their charges every year in April, and these wholesale charges make up the majority of a business water bill. Ofwat sets the price controls which govern the level of wholesale charges and determines the maximum level of retail charges.

How much will my bills change?

Castle Water is required to pass through wholesale increases, so these changes directly affect your bill. Our retail charges make up a small proportion and are not the main driver of this increase.

Many areas will see increases ranging from 5% to over 15%, depending on region, usage type, and whether wastewater or trade effluent services are involved. You can find a summary of the changes in each area in our CEO John Reynolds’ review of April 2026 tariff increases.

What is my increased bill paying for?

Ofwat has approved a £104 billion investment programme for 2025–2030 to address ageing networks, improve water quality, protect the environment, and reduce leaks. This investment is partially funded through the wholesale water charges paid by all customers.

How you can manage the impact

There are a few steps you can take to help manage the impact of these changes:

• Submit regular meter readings to ensure your bills are accurate. You can submit a reading quickly and easily via the Customer Portal.
• Review the water efficiency measures available to your business.
• Look for opportunities to reduce your consumption, particularly if you are a high-usage site.