Tánaiste Eamon Gilmore has told the Dáil that he does not agree with a flat charge for water.
He was responding to a question from independent TD Catherine Murphy on behalf of the Technical Group.
Mr Gilmore said that he had said clearly that Ireland needs a system based on there being a free allowance constructed in a way that takes account of different circumstances of different families.
He said that it was clear that families with children have particular needs and that families that have a medical situation have different needs.
He said there should be metering to encourage conservation of water, which would enable families to reduce their water bills.
Ms Murphy said water charges were a lightning issue on the doors and people were wondering what they paid their taxes for.
Earlier, Minister for the Environment Phil Hogan told the Dáil that a study carried out by his department has identified between 48,000 and 50,000 apartments and multi-occupancy properties that can be fitted with water meters next year.
He said that of the estimated 1.35 million domestic properties connected to public water supplies, about 300,000 properties will not be metered as part of the current phase of meter installation due to the cost or technical difficulty in doing so.
These properties include apartment blocks and other multi-occupancy buildings and houses with shared service connections.
But a study carried out by engineers at his department has found that 48,000-50,000 of these properties can now be metered.
The minister expects that at least 400,000 meters will be installed by the end of this year,
He was responding to a question from Fianna Fáil TD Barry Cowen during this morning's Ministers' Questions about the number of households who will not have a water meter by the time charges are introduced.
Mr Hogan said that charging by usage is the fairest way to charge for water and the Government has decided that meters should be installed.
He said that 200,000 water meters have been installed to date under the national domestic water metering programme.
Irish Water has indicated that it will have installed at least 400,000 meters by the end of this year with 1.058m properties to be metered by the end of 2016.
Of the estimated 1.35 million domestic properties connected to public water supplies, about 300,000 properties will not be metered as part of the current phase due to the cost or technical difficulty in doing so.
These properties will include apartment blocks and other multi-occupancy buildings and houses with shared service connections.
Mr Hogan added: "My department has funded a study, commissioned by Irish water, on possible approaches to metering these properties but not as part of the current metering programme but would be part of a programme in 2015. The findings of this report are currently being assessed."
Domestic water charges are due to commence on 1 October this year and the first bills will be introduced in January 2015.