The Tánaiste says Irish Water should not be a high-cost operation.
Joan Burton has warned that the utility could be rejected by the public if it passes on too many costs to householders.
The energy regulator is due to make a final decision in the coming months on exactly what costs Irish Water can pass on to the public.
Speaking at the MacGill Summer School in Donegal, Burton said she wants Irish Water to keep costs down.
"I will just say this: I don't believe in a gold-plated Irish Water," she said.
"If you set up a full cost, high-cost model, obviously that may lead to difficulties down the road. What I would like to see is an efficient and cost-effective Irish water model, and I've said that from the beginning."
Irish Water said it will be liaising with the Data Protection Commissioner on its request for PPS numbers for each individual in a household, including children.
The first bills for water charges will be issued early next year, for usage for the last part of 2014.