Three water businesses owned by France's Veolia and serving more than 3.5 million people have been sold in a deal worth £1.2 billion.
Veolia Water's Central, Southeast and East businesses, which cover towns including St Albans, Dover, Woking and Harwich, are to be sold to an infrastructure fund managed by Prudential-owned M&G and Morgan Stanley.
The three water companies have a combined annual turnover of £274 million and collectively employ around 1,250 people.
Veolia Water, which will retain a 10% stake in the water supply businesses, said the move would allow it to focus on its work as a leading provider of outsourced services to the UK water industry.
More than 1,000 people work for Veolia Water Outsourcing, helping to generate turnover in excess of £400 million a year.