Irish Water has said it costs about 25 million euro to bill the public.
The utility also told a parliamentary body that it is doing the job of supplying clean tap water and treating sewage cheaper than the 34 councils it took over from in 2014.
Irish Water said about 13 million euro is spent processing household bills while a call centre costs about 10 million euro to run and another two million euro goes on wages for staff.
The utility was joined by the Commission for Energy Regulation (CER) at the Oireachtas Committee on the Future Funding of Domestic Water Services as it began exploring how water will be paid for since charges were cancelled last year until the end of this March.
Irish Water told the hearing that it would need 239 million euro from the state in 2017 if bills were not reintroduced.
Michael McNicholas, chief executive of parent company Ervia, claimed that Irish Water is doing its work cheaper than the councils did up until 2013.
But he said he could not put a figure on how much is being saved by having a single state body in control.
He told the committee that Irish Water has already cut its running costs by 70 million euro since it took over in 2014.
“We can absolutely say that we are providing it at a lower cost,” Mr McNicholas said.
The hearing took place on the back of a submission by the CER watchdog which said that no new metering should take place once the current contracts finish at the end of this month.
It said Irish Water has only set aside two million euro in the next two years for metering.
So far 58% of households – 884,000 customers – have had meters installed on the edge of their properties and a lmost 700,000 thousand properties are yet to be monitored on the grid.
Irish Water said that about 200,000 homes were technically difficult to include in a standard metering programme and that it passed over some areas for safety reasons.
It said other properties could be metered in the future when deeper infrastructural works were being carried out such as pipe replacement and repair.
Commissioner Paul McGowan defended the idea of no more meters being fitted.
“We made no bold statement that metering should be abandoned. If you want to characterise it, I’d say parked,” he told the committee.
Irish Water also said it has benchmarked its set-up costs with other utilities and claimed that it was created 100 million euro cheaper than any other similar utility anywhere else in the world.
It defended 70 million euro spent on consultants, advisers and international experts in its first year, including software and hardware engineers.
“No other utility has done anything of that scale for the same cost,” Mr McNicholas said.
He said the money was not wasted and that it was necessary and efficiently spent and 100m euro cheaper than any other company could do it.
