The Food and Drink Federation, which is the trade body for food and drink manufacturers in the UK, said the 21 brands that had agreed the measures had a combined annual turnover of £15bn and aimed to cut 2007 water usage levels by 20% by 2020.
The brands that have so far signed up to the voluntary agreement, known as the Federation House Commitment, have said that it could save the 140m litres of water being used by businesses each day within six months, and make a combined saving of £60m a year.
Brands that have joined the agreement will work with Envirowise, a government funded consultation service for companies aiming to cut energy usage, to develop ways of reducing their impact on the environment.
The brands involved have committed to find ways of reducing their water usage in the next six months and give Envirowise annual reports outlining their progress.
Callton Young, director of sustainability and competitiveness at FDF, said: "Last October FDF chose to be bold about the environment by targeting priorities where we can make the biggest difference through collective action.
"[The] signing of the Federation House Commitment by many of our largest member companies is an important demonstration of this commitment and their desire to reduce the environmental impacts of our sector through the widespread adoption of water efficiency best practice."
The full list of companies that have so far signed up to the agreement also include Britvic, Premier Foods, United Biscuits, Coca-Cola Enterprises, Apetito, Birds Eye Iglo, Kellog Marketing & Sales, Kraft Foods UK, Mars Snackgood, Muller Dairy UK, PepsiCo UK, UIN Foods, Unilever UK, Uniq, Warburtons, Weetabix and Young's Seafood.