A meeting where a scathing review of Wellington Water was discussed saw Upper Hutt's mayor lash out over its failings, while other council leaders aired their problems with its deep-seated cultural issues.
An independent report revealed Wellington Water staff took four months to tell the region's councils about a $51 million budgeting error.
It also found the company was immature, with inadequate systems and processes and a dysfunctional culture.
It compared the $5m accounting mistake to the fluoride scandal just two years earlier.
Wellington Water were also the subject of a report conducted by consultant company FieldForce4 released earlier this year, initiated by Wellington City Council.
A Wellington Water committee meeting amongst mayors in the Wellington region was held on Friday morning to discuss the latest review.
Part of the meeting was excluded to the public due to privacy concerns which Upper Hutt mayor Wayne Guppy was not happy about.
"There's a cover up again, we've had the fluoride report, we had the FieldForce report that this committee did not want to address, and to not [want] to discuss this in public is disgraceful."
When the public were allowed back in the meeting, Guppy made it clear the problems with Wellington Water were not new.
"We've allowed this beast to grow and it's over five or six years and the fact of the matter is they have continuously thumbed their noses at us."
He hoped other council-controlled organisations around the country were not run like their councils ran Wellington Water.
Wellington Water board chairperson Nick Leggett said they were taking responsibility for the botch up.
"Ultimately the board's accountable for the performance of the company and we're going to take account and we're going to improve things."
Leggett would not comment on whether anyone in senior leadership would be sacked over the saga.
"Today is about understanding at a high level what the direction from our shareholders is."
He said Wellington Water was an organisation that was scared to tell the truth and confront problems.
"That's what we've got to change, we have to be up front earlier."
Lower Hutt mayor Campbell Barry said there was clearly cultural issues that need to be addressed immediately.
"I think we are very clear on that; the board is clear on that, and we are expecting action.
Wellington mayor Tory Whanau and Porirua mayor Anita Baker shared similar sentiments.
Baker said the review showed there were massive failures at Wellington Water and that its culture had to change.
Whanau said the review was honest and reinforced serious issues that Wellington City Council had highlighted in the FieldForce4 report and the fluoride inquiry.