Exeter-based water utility Pennon Group has acquired Bristol Water following an £814 million deal.
The acquisition agreement includes an assumed debt of approximately £389 million.
Bristol Water currently serves an estimated 1.2 million customers.
Pennon has also announced it will also distribute to its shareholders a dividend of £1.5 billion.
Susan Davy, Group Chief Executive of Pennon Group, said: “We see attractive opportunities to continue to invest in the Bristol Water business to deliver enhanced resilience and water security to benefit customers in Bristol and beyond.
“This latest acquisition, building on a strong heritage and history, firmly cements Pennon as one of the leading UK water and waste water companies.”