The head of Irish Water's parent company has defended the water utility for running €100m over budget on the installation of water meters.
Ervia chief executive Michael McNicholas has also denied he has a conflict of interest from his work for a company which has water contracts.
Mr McNicholas said there was one final estimate of €539m for water meter installation and Irish Water would hit this figure.
"In late 2012 the Department asked Bord Gais to put together an estimate of what they felt the overall metering programme would cost, and they came up with an estimate of €430m.
"That was an estimate, and they made it very clear at the time that the final figure for this project would only arrive as a result of going to the market and tendering for the contract," Mr McNicholas said on RTE radio.
"There is a €100m difference between the estimate that we had at the end of 2012 and the final contracted figure."
He said there were three reasons for the €100m gap:
l The estimate was taken before Bord Gais received survey details from local authorities.
l Three regional contracts to spread the workload.
l Contractors wouldn't sign up for the bid price.
Mr McNicholas said the company went to the market in a full procurement process. He said Irish Water will come in on budget at €539m.
"At the moment we are on target and ahead of budget," he said.
Mr McNicholas said that at this stage just over half a million meters have been installed out of a total of around a million.
He said there are a number of pockets, around a half a dozen mainly in Dublin and Cork, where meter installation has been stopped due to protests.
He also said Irish Water has fixed around 500km of the water network in 11 months.
"In 18 months we will have all the 20,000 people on boil water notices off those notices," said Mr McNicholas.
Meanwhile, many of the country's local authorities have refused to say whether they will evict tenants who do not pay their water charges.