United Utilities chief executive Philip Green will be replaced by Steve Mogford, the chief executive of defence electronics group Selex Galileo, when he steps down at the end of March.
Mr Green is set to net as much as £4m in shares and options on his departure, including 100,000 free shares from a deal when he joined United in 2006 that the company would match his self-funded share purchase if he stayed at least five years.
During his tenure Mr Green has refocused the group, selling a swathe of non-core business units including a gas pipeline network, its Australian subsidiary, outsourcing contracts and operations in Bulgaria, Estonia and Poland.
Mr Mogford, 54, started his career at British Aerospace. Before joining Finmeccanica-owned Selex Galileo, he was chief operating officer at BAE Systems.
United's chairman John McAdam said: "We are appointing a strong chief executive with the capability to lead United Utilities through the next stage of its development.
"We have a plan to invest £3.6bn in the North-west over the next five years and Steve is the right man to lead that programme."