John Mullins of Bord Gáis said average bills across Europe fall within that bracket and as Irish people were among the highest consumers of water in the continent, they could fall into the higher end of the bracket.
News of the possible fee comes amid speculation that households might be hit with flat rate water charges, since the Government will not be able to install meters in all households by the 2014 date the Troika has suggested.
Mr Mullins admitted the Exchequer will have to fund the system, even though business and domestic customers will be charged.
He said: “The Exchequer is still going to have to fund the industry for many years to come because we have under-invested in the water sector, and then quite clearly Bord Gais is going to raise funds from its own balance sheet, essentially to assist, so there is flexibility.
“That is something that the Commission for Energy Regulation is going to have to look at and then come up with a number. That is appropriate, but then the objective is to have a better water system and one that is more efficient.”