Under the three-year agreement, Edinburgh-based Business Stream will supply water to Bernard Matthews’ meat factory at Holton, in Suffolk, and will offer advice on water and waste efficiency.
Mark Powles, chief executive of Business Stream, said: “This is a very significant deal for the prospect of competition south of the Border since it demonstrates that business customers in England are willing to switch suppliers.
“Signing a deal with Bernard Matthews sends a clear message to the UK that we have the ability to provide a quality service to major British brands.”
Rob Mears, Bernard Matthews’ UK managing director, added: “Having a free choice of water supplier is an important development for us.”
At present, only sites in England that use more than five million litres of water a year can switch from using their local supplier.
The coalition government published a draft water bill last year to deregulate fully the business market south of the Border, a measure introduced in Scotland in 2008.
In September, Business Stream hired former SSE director David Seymour to lead its push in England. Powles has suggested that opening up the English market could also increase competition in Scotland.