Auckland Mayor Len Brown, who has overall responsibility for the budgets of the CCOs, said their cost structure was inherited by the Auckland Council and would be part of a review of the CCO model, expected to start in the second half of next year.
"I am keen to see if there is a better way to deliver council services," he said. "I am sure there are savings we can make."
The CCOs are overseen by 49 unelected directors, who each earned between $35,000 and $106,000 in the past financial year at a total cost of $2.43 million.
Between them, the seven chief executives earned about $2.6 million in salaries and about $8.1 million was paid to other CCO executives.
The chief executive salaries range from $330,000 for the head of Auckland Tourism, Events and Economic Development, Brett O'Riley, and Auckland Council Investments' Gary Swift, to about $710,000 for Watercare boss Mark Ford.
Mr Ford's salary is out of kilter with the others'. He earns about 22 per cent more than the $580,000 paid to Auckland Transport boss David Warburton, who on paper has a bigger and more complex job.
Watercare is the CCO to earn the big bucks. As well as Mr Ford's salary, the executive team cost ratepayers $3.5 million and the water company has 120 staff earning more than $100,000 and 19 on more than $200,000.
By comparison, the executive costs for Auckland Transport are $2.9 million and while more staff - 169 - earn more than $100,000 the transport body has fewer - 12 - on more than $200,000.
The Herald estimates that Mr Ford's salary is the equivalent cost of Aucklanders taking about 9.5 million showers.
Watercare chairman Ross Keenan defended Mr Ford's salary, saying it had been independently evaluated and reviewed by the remuneration consultancy Strategic Pay.
Mr Ford, who rejoined Watercare in 2010 after being the executive chairman of the agency that set up the Super City, started on a base salary of $630,000 with an incentive bonus of 15 per cent.
Mr Keenan said Mr Ford received most of the at-risk bonus in the past year, plus a 3.5 per cent pay rise.
His salary was also checked at the outset to ensure it was below the salary of $675,000 plus 10 per cent bonus for council chief executive Doug McKay.
Mr Keenan said Mr Ford's salary still included an incentive bonus of 15 per cent, half of which was based on financial measures and half on professional and relationship achievements.