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Business water suppliers in the UK

This guide is for the research stage: you want to know which licensed water retailers serve businesses, who owns them, and which would fit a portfolio like yours. There are 22 active retailers in the English market, open to competition since 1 April 2017; Scotland opened in 2008. The profiles below are even-handed: no retailer pays for placement and none of this is a ranking.

Active retailers
22
Business customers
~1.2M
England open since
1 Apr 2017
Tender these retailers for my sitesWho is my water supplier?

Retailer or wholesaler: which one is your supplier?

Every business water bill involves two companies. Knowing which is which is the difference between researching the right shortlist and phoning a company that cannot help you.

Retailers bill and serve you

The companies profiled on this page. They meter, bill, handle queries and add services like leak alerts. This is the only layer you can choose, and the only layer worth tendering.

Wholesalers pump and treat

Regional monopolies (Thames Water, Severn Trent, United Utilities and others) that own the pipes and set the non-negotiable wholesale charge. See the full regional map on our business water and wastewater hub.

Not sure which retailer currently bills a site? Our free postcode lookup identifies your likely wholesaler and where to find your retailer on the bill.

Find my water supplier

Already past the research stage? Our guide to how to compare business water suppliers covers the comparison criteria and tender process; this page is the directory behind it. For the wider market context, see how the UK utilities markets are structured.

The UK business water retailers, profiled

Nine of the 22 licensed retailers: the five largest by supply points on the MOSL dashboard (March 2026 snapshot), then four further significant retailers in alphabetical order. Every profile sticks to verifiable facts; we publish no review scores or pricing claims because both change too often to be reliable.

Business Stream

Wholesaler-owned

391,664 supply points (MOSL, March 2026)

Ownership and heritage

Wholly owned by Scottish Water (the legal name is Scottish Water Business Stream Limited). Acquired Yorkshire Water Business Services on 1 October 2019, and positions itself as the first retailer to have operated in a competitive water market, a reference to Scotland's 2008 opening.

Known for

Scale. The largest retailer by supply points on the MOSL dashboard, with a presence in both England and Scotland.

Typically suits

Multi-site portfolios that span England and Scotland, and larger organisations that want the biggest incumbent on the shortlist.

Read the full Business Stream profile

Castle Water

Independent

199,306 supply points (MOSL, March 2026)

Ownership and heritage

Founder-led independent. Acquired the Thames Water non-household customer book in 2017 and Brightwater on 7 February 2025.

Known for

The second-largest supply-point count on the MOSL dashboard, much of it inherited from the Thames Water book at the market opening.

Typically suits

Thames-region businesses reviewing arrangements they never actively chose, and buyers who want a large retailer that is not wholesaler-owned.

Read the full Castle Water profile

Water Plus

Joint venture

Top 5 by volume (MOSL, March 2026)

Ownership and heritage

A 50/50 joint venture between Severn Trent and United Utilities, approved by the Competition and Markets Authority in May 2016 ahead of the English market opening.

Known for

Combining the business retail operations of two of the largest English wholesalers, giving it a heavy footprint across the Midlands and the North West.

Typically suits

Mid-market portfolios concentrated in the Midlands and North West that want one retailer across both parent regions.

Read the full Water Plus profile

Wave Utilities

Joint venture

Top 5 by volume (MOSL, March 2026)

Ownership and heritage

A 50/50 joint venture between Anglian Water and Northumbrian Water Group, formed for the 2017 English market opening.

Known for

A top-five supply-point count on the MOSL dashboard, anchored in its parents' eastern and north-eastern regions.

Typically suits

Portfolios weighted towards the East of England and the North East that want a wholesaler-backed retailer.

Read the full Wave Utilities profile

Pennon Water Services

Joint venture

Top 5 by volume (MOSL, March 2026)

Ownership and heritage

A joint venture between FTSE-listed Pennon Group (parent of South West Water) and South Staffordshire, trading as Source for Business.

Known for

Supporting over 150,000 business customer accounts across the UK, citing over 25 years of water, wastewater and trade-effluent management expertise.

Typically suits

South West and Staffordshire-area businesses, and national portfolios that want a listed group behind the retailer.

Read the full Pennon Water Services profile

Clear Business

Independent

135,000+ customers across the Verastar trading names

Ownership and heritage

The water brand of the Verastar group, a multi-service provider for small businesses with more than 135,000 customers across its trading names, operating in both Scotland and England.

Known for

One account across several services: water sold alongside energy, broadband, phone and insurance.

Typically suits

Micro and small businesses that want their utilities consolidated with a single provider and a single bill.

Read the full Clear Business profile

Everflow

Independent

Private-equity backed (Perwyn, since June 2018)

Ownership and heritage

Founded in 2015 by Josh Gill and based in Stockton-on-Tees, with private-equity backing from Perwyn since June 2018. Runs its own utilities billing platform, Everflow Tech, alongside the retail business.

Known for

An automation-led billing model aimed at smaller businesses; it has grown quickly since the 2017 opening, supplying England and Scotland.

Typically suits

Single-site SMEs that want simple, automated billing without a heavyweight account structure.

Read the full Everflow profile

SES Business Water

Wholesaler-owned

Business retail arm of the SES Water group

Ownership and heritage

The business retail arm of the SES Water group, whose wholesale area covers parts of Surrey, Kent, West Sussex and south London. Pennon Group acquired SES Water from its Sumitomo Corporation and Osaka Gas owners in January 2024.

Known for

Regional roots in the south-eastern wholesale area.

Typically suits

Businesses south of London that want a regionally rooted retailer with a long local heritage.

Read the full SES Business Water profile

Water2business

Joint venture

Around a 6 per cent market share (Pennon Group)

Ownership and heritage

Jointly owned by Wessex Water and Bristol Water, with roots in a joint billing venture the two companies set up in 2000. Took on both parents' business customers when the English market opened on 1 April 2017; Pennon Group now holds a 30 per cent share through its Bristol Water acquisition.

Known for

Water-efficiency advice and leak-detection services offered alongside billing, anchored in the Wessex and Bristol regions.

Typically suits

West of England businesses, and sites that want efficiency support bundled with the retail contract.

Read the full Water2business profile

Supply-point counts from the MOSL Power BI dashboard (March 2026). The remaining licensed retailers include regional and niche specialists; we tender across the whole panel, not just the names above.

How we assess retailers

  • Whole-of-market panel. We tender across the licensed Open Water retailer panel, not a single referral partner, and score offers on margin, billing quality, consolidation capability and trade-effluent expertise.
  • How we are paid. A commission within the retail margin, disclosed on every tender, with the wholesale charge, retailer margin and our margin shown separately. Our commissions calculator shows exactly how broker pay works.
  • No retailer pays for placement. The profiles above are descriptive, not a ranking. Scale figures come from MOSL, ownership facts from the companies and their regulators, and anything we could not verify has been left out.

Which retailer is right for your portfolio?

The honest answer is that it depends on your sites, not on any league table. This is how we shortlist by buyer type.

Single-site SME

Your retail margin is small in pounds but easy to overpay. Automation-led independents and incumbents with a sharpened margin both belong on the shortlist; what matters is accurate metering, clean billing and a fair retail charge.

Send us one recent bill and we tender the retail layer across the panel.

Multi-site mid-market

Consolidation usually beats headline margin: one retailer, one invoice, one renewal date across every wholesale region in the portfolio. Shortlist retailers with proven multi-region capability and bill-validation support.

One bill per site is enough for a consolidated tender.

I&C and trade effluent

Industrial sites need a retailer that can handle trade-effluent consents, Mogden formula charging and surface-water rebate audits, with a named account team. The shortlist is shorter and service weighs as heavily as price.

We run the Mogden review and rebate audit alongside the tender.

For worked examples, see how we consolidated multi-utility supply for food producer Good Taste Bakery and managed an education portfolio for Watford Grammar School for Boys. When you have a shortlist, our guide on how to switch business water supplier walks through the CMOS process step by step.

Get a broker-led retailer shortlist

Business water suppliers: FAQs

How many business water suppliers are there in the UK?
There are 22 active licensed retailers in the English market, serving roughly 1.2 million non-household customers across about 2.6 million supply points (SPIDs). English non-household water spend is around £2.5 billion a year. Scotland runs its own licensing regime, and several retailers hold licences in both markets.
Can my business choose any licensed water retailer?
Any non-household customer in England has been free to choose its retailer since the market opened on 1 April 2017. Scottish businesses have had the same right since 1 April 2008. Wales is only partially open: sites using more than 50 megalitres a year can switch. The retailer must hold a licence for the market your site sits in.
Who is the largest business water supplier?
Business Stream is the largest retailer by supply points, with 391,664 SPIDs on the MOSL dashboard (March 2026 snapshot). Castle Water is second with 199,306. Water Plus, Wave Utilities and Pennon Water Services complete the top five by volume.
Do water retailers set the price of the water itself?
No. The wholesale charge, typically 80 to 95 per cent of the bill, is set by your regional wholesaler under Ofwat's PR24 price review and is identical whichever retailer bills you. Retailers compete on the retail layer: their margin, billing accuracy, query handling and added services such as leak alerts.
Do I have to stay with the retailer my wholesaler set up?
No. When the English market opened in April 2017, most business customers were transferred to a default retailer, often one owned by or descended from their regional wholesaler. You are free to switch to any licensed retailer, and the water reaching your taps does not change. How to switch business water supplier.
What happens if my water retailer goes bust?
Your supply continues, because the regional wholesaler keeps pumping and treating water regardless of the retailer's finances. The market has interim supply arrangements that move a failed retailer's customers to another licensed retailer, though deemed rates can apply until you agree a new contract. What happens when a water retailer goes bust.
Who regulates business water retailers?
Ofwat issues the water supply and sewerage licences in England and oversees the market codes. MOSL, the market operator, runs the central settlement system (CMOS), which processes around 90,000 transactions a day between retailers and wholesalers. In Scotland the retail market is regulated by the Water Industry Commission for Scotland.

Skip the directory research, tender the lot

Send us a recent bill per site. We tender the licensed Open Water retailer panel, show the wholesale charge, retailer margin and our margin separately, and stay with the account for the term.

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