Mr Cleary was formally appointed on Friday after serving as acting chief executive officer for several months after the departure of predecessor Jim Bentley.

Mr Bentley was named the NSW government's chief executive officer for the NSW water sector last year.

"I am confident Darren will continue to provide strong leadership at Hunter Water, building on his extensive experience at the agency, including most recently as acting chief executive officer since February," Mrs Pavey said.

"Darren brings more than 25 years' experience working for utilities in the water sector and his appointment will allow Hunter Water to continue to deliver on its outstanding customer experience, while advancing key policy and strategy areas."

The appointment followed an international search for the organisation's next leader, Hunter Water chairman Terry Lawler said.

"This is a challenging time for everyone in our organisation and community," Mr Lawler said.

"We are confident selecting Darren to lead Hunter Water on a permanent basis ensures Hunter Water remains well positioned to continue to deliver its essential services to the community."

Mr Cleary is also a director of the Board of the Committee for Hunter and a Newcastle Institute for Energy and Resources advisory board member at the University of Newcastle.