The head of Irish Water says the consultancy services that cost 50 million euro sought by the company were value for money.
The body now responsible for the supply of water says the spending of such money was necessary in creating a new utility service - costs which will have to be recouped by the company.
The company says as yet there has been no decision made on what charges people are likely to face but they have warned that those who do not pay their water charges will face a disruption to their service.
And John Tierney told Newstalk Breakfast that further costs in the set up of the water charging system can't be ruled out.