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Too many businesses are still paying water bills based on estimates — and that means overpaying for water they haven’t used, or getting hit with catch-up charges further down the line. It doesn’t have to be that way.
In the latest February 2026 rankings released by MOSL, the water market operator for England, Castle Water is once again number one for traditional meter reads, which require a site visit and account for 87% of the total market. Castle Water held the same top position in January 2026.
The data is clear: Castle Water is doing more than anyone else to ensure customers are billed on what they actually use.
The remainder of the market consists of smart meters, which transmit readings automatically. Currently, 32% of the market’s smart meters are served by Castle Water — and 25% of Castle Water’s total meter population is now smart. This offers customers a distinct advantage through enhanced read reliability and delivers more detailed insights into their water consumption and sharp control over costs.
Regular meter reads ensure customers enjoy accurate bills based on their actual usage rather than estimates, which can risk overpayment or ‘catch-up’ charges.
Dedication to Billing Accuracy
The latest figures from MOSL in 2026 underline Castle Water’s continuing dedication to customers after consistently being identified as the top-performing large business water retailer for meter reading throughout 2025.
John Reynolds, CEO of Castle Water, said: “Accurate billing is vital for any business, and meter reading is the foundation for helping our customers avoid overpaying for water they have not used, or getting hit with catch-up charges down the line.
“Businesses across the UK should demand the best from their water retailer. We passionately believe in that message and continue to heavily invest in systems so that we can lead the market and champion our customers.”
Switch to Castle Water: 100% Accurate billing from Day One
When you switch to Castle Water, you get 100% transfer reads — that’s no estimates from day one. MOSL’s February 2026 data confirms it: Castle Water is the only retailer hitting that mark. No other retailer comes close.
“When a business puts its trust in Castle Water, our goal is to ensure that the relationship gets off to the best possible start with the foundations built on accuracy and responsiveness,” said John.
Transfer Meter Reads Submitted to Market (MOSL, February 2026)
| Name |
Rank |
Reads |
Late Reads (Days)* |
| Castle Water |
1 |
100.00% |
0.00 |
| Water Plus Group |
2 |
93.47% |
11.77 |
| Business Stream |
3 |
96.87% |
14.33 |
| Water2Business |
3 |
98.05% |
15.00 |
| Wave |
3 |
95.00% |
13.22 |
| Everflow |
6 |
92.68% |
12.99 |
| Pennon Water Services |
7 |
77.49% |
– |
*Ranking based on average across all transfer metrics
Switching Water Retailer Is Easy
Still paying on estimates? That’s money you may not owe. Demand better — switch to a retailer that will actually read your meter. Switching to Castle Water takes minutes and costs nothing.
Using Castle Water’s instant quote tool, businesses can get an immediate view of their new charges and initiate the switch process. A 5-star customer service team then take care of the switch, ensuring it’s a smooth, seamless transition from the current supplier.
New customers often benefit from savings simply by stopping overpayments on estimated bills, with switching bringing a host of other benefits, including:
- Advanced online account management
- The ability to track water usage to maximise savings
- Transparent, fairer bills
- Fewer billing disputes
- Improved cash flow
