There's continued speculation that the new Government may abolish the utility, but internal estimates claim the move could cost the tax payer around 7 billion euro.
It includes around 100-million euro in pay outs to staff who couldn't be transferred elsewhere.
The cost has been questioned by anti-water charge protesters – who say the closure would save money in the long term.
But Secretary of the Irish Water Group of Unions, Adrian Kane, says workers don't have other jobs to go to.
