A leading economist says Irish Water's economic viability is "damaged" by the Government's announcement of a package of new charges and measures yesterday.
A former economist with the ESRI, John Fitzgerald, said the utility will bring in about €500m, but may need almost twice that sum.
He said the Government would now need to continue to provide Irish Water with a subvention and the company's revenue stream might not be enough to see it declared "independent" by auditors.
John Fitzgerald said that could leave the Government with a significant bill.
He said: "If Irish Water is not independent, (any shortfall) is going to have to come out of taxation. The Government could find itself with a bill for €300m or €400m next Autumn for investment that needs to be undertaken and that was going to be borrowed by Irish Water.
"(Now,) that borrowing might be declared part of the Irish borrowing requirement and may have to come out of taxation."