Ervia's annual report for 2016 has revealed that they paid former Irish Water managing director John Tierney €655,000 in salary, severance and pension contributions.
The report from Irish Water's parent company shows he was paid €573,000 on retirement in April last year.
It reveals that €100,000 was a severance payment while the other €473,000 was paid into the Ervia defined benefit pension scheme.
He also earned a salary of €67,000 in the months leading up to his retirement last year.
He also got €11,000 in pension contributions made on behalf of the Managing Director and €4,000 in other benefits, including cost of company car and health insurance.
Irish Water said that Mr Tierney "carried his full service to his new employer and, in line with Government guidelines regarding the transfer of staff from local authorities to Irish Water, his retirement arrangements are exactly the same terms that would have applied had he retired as Dublin City manager."