Water · Updated 24 August 2026

Business water bill errors: how to spot overcharging (and claim it back)

Water bills are among the least-checked costs a business has — which is exactly why overcharges hide on them. Here is what to look for before you even think about switching.

Business water bills are among the least-scrutinised costs a company has — which is exactly why errors on them so often go unnoticed. Since the market opened, businesses in England and Scotland can switch retailer, but before you even think about that, it is worth checking you are not being overcharged on the bill you already have. Here is what to look for.

Your bill has more than one charge

A business water bill is usually made up of separate lines: clean water (what is supplied to you), wastewater or sewerage (what is taken away), and often surface water and highway drainage (rainwater running off your site into the sewers). Each is charged differently, and each is a place an error can hide.

The most common overcharges

How to check your bill

Read each line of the bill and ask a simple question of each: does this apply to my site? Look especially at the drainage charges, check whether recent reads are actual or estimated, and compare your usage against what you would expect. If something looks off, it is worth querying with your retailer.

Overcharges can sometimes be corrected retrospectively, so a review can uncover not just future savings but backdated refunds — occasionally worth more than switching retailer.

Then consider switching

Once your bill is accurate, you can look at whether a different retailer offers better service or terms. Remember you are only switching the retailer that bills you — the water itself, and the pipes, do not change, so there is no disruption. We explain the process in our guide on switching your business water supplier.

How Win Energy helps

We review business water bills and compare business water retailers across the market — and because we look at the bill line by line, we can flag the kind of drainage and estimation errors that quietly add up. We will be honest, too: where the real saving is in fixing your existing bill rather than switching, we will say so.

Not sure if your water bill is right? Send us a recent copy and we will check it over — free, no obligation. Call 0845 862 1947 or get in touch.

Water is easy to pay on autopilot, which is exactly why it is worth a proper look. Check each charge applies to your site, make sure your reads are real, and query anything that seems wrong — and you may find the cheapest saving of all is the one you were being overcharged for.

FAQ

Water — Common Questions

It is common. Businesses are often charged for surface-water drainage they do not use, billed on estimated rather than actual reads, or put on the wrong meter size or tariff. A line-by-line check can find corrections and sometimes backdated refunds.
It is a charge for rainwater that runs off your site into the public sewers. If your site drains elsewhere, such as to a soakaway, you may be able to have the charge removed.
Often yes. Errors can sometimes be corrected retrospectively, so a review can uncover backdated refunds as well as future savings.
No. You only change the company that bills you and manages your account. The water and the pipes stay the same, so there is no interruption.

Ready to act on this?

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Last reviewed 24 August 2026. Figures are based on Ofgem, NESO/National Grid, gov.uk and published industry data, and are correct to the best of our knowledge at the time of writing; prices, rates and regulations change, so always confirm current figures before making a decision. This guide is general information, not financial, legal or regulatory advice. Win Energy Ltd is an independent utility broker (not a supplier); any savings are illustrative and vary by business.
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