Business water FAQs

Yes, if you are a non-household customer in England or Scotland. England's water market opened to competition on 1 April 2017, Scotland's on 1 April 2008, and around 1.2 million businesses, charities and public-sector organisations are now eligible. Wales is only partially open: Welsh businesses must use more than 50 megalitres a year to switch. Households cannot switch anywhere in the UK. If you are eligible, switching your business water retailer changes who bills you, not the water itself.

Open Water is the competitive retail market for non-household water and wastewater in England, launched on 1 April 2017. Regional wholesalers keep their monopoly on pipes, treatment and wastewater removal, while licensed retailers compete to bill, meter and serve business customers. The English market covers roughly £2.5 billion of annual non-household spend across about 2.6 million supply points. Our guide to business water and wastewater explains how the two layers fit together.

The wholesaler owns the physical network: it pumps water to your site, removes wastewater and sets the non-negotiable wholesale charges under Ofwat's PR24 price review. The retailer is the company that bills you, handles meter reads and queries, and adds a competitive margin on top. There are 12 wholesalers in the English non-household market and 22 active retailers. You cannot choose your wholesaler, but you can choose from the licensed business water suppliers that retail in your region.

MOSL (Market Operator Services Limited) runs the English non-household water market. CMOS is its central system: it records every supply point, processes retailer switches and handles roughly 90,000 transactions a day. A SPID (Supply Point Identifier) is the unique reference for each water or sewerage supply point, and there are about 2.6 million of them on CMOS. You do not need to track any of this yourself: send one bill per site and we map every SPID when you request a business water quote.

There is no single national rate. As at May 2026, indicative wholesale-led ranges run from roughly £0.85 to £1.90 per cubic metre for water and £1.15 to £2.20 per cubic metre for wastewater, depending on your region and how much you use. Larger users sit at the lower end of each range, and standing charges and retailer margin sit on top. The full breakdown by business size is on our business water rates and charges page.

Because the wholesale charge, typically 80 to 95 per cent of the bill, is set by your regional wholesaler under Ofwat's PR24 price review covering 2025-2030, and each wholesaler sets its own tariffs. A site in the Thames Water region pays different wholesale rates from one in the Northumbrian Water region, and no retailer can change that. To see which wholesaler serves your site, use our business water supplier postcode lookup.

Four main lines: a volumetric water charge (pence per cubic metre), a fixed standing charge per meter, wastewater charges (foul sewage, surface-water drainage and highway drainage) and the retailer's margin. The wholesale elements make up roughly 80 to 95 per cent of the total and are not negotiable; the retail layer, typically 5 to 15 per cent, is where competition and billing errors both live. Our guide to reducing business water bills walks through each line and where the savings sit.

Most businesses do not. Water and sewerage supplied to non-industrial customers (offices, retail, education, hospitality) is zero-rated for VAT. Industrial customers whose activity falls in SIC code divisions 1 to 5 (extraction, manufacturing, construction, energy and mining) pay the standard 20 per cent rate, and there is no Climate Change Levy on water at all. Mis-set VAT categories are one of the most common billing errors we find: see our guide to VAT on business utility bills and our checklist for cutting business water costs.

The most common causes are a hidden leak, a catch-up bill after a run of estimated meter reads, or a tariff or VAT category change. Overnight and weekend consumption on a site that should be empty is the classic leak signature. Before you query the bill, rule the leak out: our business water leak check walks you through a simple meter test and explains the leak allowance you may be able to claim.

Four levers. Tender the retail layer, typically 5 to 15 per cent of the bill, across the Open Water retailer panel. Fix billing errors such as a wrong VAT category or long runs of estimated reads. Audit surface-water drainage charges, which many sites pay on areas that actually drain to soakaway or watercourse, with rebates going back six years where applicable. And catch leaks early with meter-level monitoring. Our guide to reducing business water bills covers all four in order of effort.

Three things: foul sewage (everything that goes down a drain inside the building), surface-water drainage (rain falling on your property that enters the public sewer) and highway drainage (run-off from adjacent roads). Most retail contracts cover all three alongside clean water, and the charges are set by your regional wholesaler. Our business water and wastewater overview explains how each element is calculated and billed.

A correction of charges for rainwater drainage your site does not actually use. Many businesses pay surface-water charges on areas that drain to a soakaway or watercourse rather than the public sewer, and where that is the case the charge can be removed and refunded, going back six years where applicable. We audit every account for rebate eligibility as standard; it is one of the quickest wins in our guide to reducing business water bills.

Trade effluent is anything a business discharges to the sewer other than ordinary domestic sewage, and it needs a trade-effluent consent under the Water Industry Act 1991. Charges are calculated with the Mogden formula, which weights the volume, suspended solids (Ms) and chemical oxygen demand (Os) of the discharge against the wholesaler's treatment costs. Food and drink, chemicals, pharmaceutical and laundry sites are typical candidates. See how multi-utility procurement worked for food producer Good Taste Bakery, or ask us to review your consents.

Often, yes. Where a leak is downstream of the meter, on your side of the supply, you may be able to claim a leak allowance for the water lost. Suspected leaks are escalated to the wholesaler for investigation, and we manage the allowance claim on clients' behalf. The first step is confirming you actually have a leak: our business water leak check walks through a simple meter test and explains how the allowance works.

Two companies do. Your retailer is the company that bills you, and its name is on your invoice. Your wholesaler is fixed by geography: it owns the pipes and sets the wholesale charges for your region, and there are 12 of them in the English non-household market plus Welsh and Scottish counterparts. If you only have a postcode to go on, our free water supplier lookup identifies your likely wholesaler in seconds.

By supply points on the MOSL dashboard (March 2026), the five largest English retailers are Business Stream (around 392,000 SPIDs), Castle Water (around 199,000), Water Plus, Wave Utilities and Pennon Water Services. All 22 active retailers buy from the same regional wholesalers, so scale is no guarantee of the best margin or service for your sites. Profiles of each are in our business water suppliers directory.

Compare the retail layer, not the water. The wholesale charge is fixed by your region, so the real differences between retailers are margin transparency, billing and portal quality, multi-site consolidation, and trade-effluent and rebate expertise. Put each offer side by side with the wholesale charge, the retailer margin and any broker margin shown separately. Our guide on how to compare business water suppliers sets out the scoring criteria we use when we tender.