The Impact trade union is calling for a constitutional referendum on protecting our water infrastructure.
The call comes as the new Government begins forming a commission to examine how the service should be paid for into the future.
The discussions were largely to blame for the delay in forming the new minority Fine Gael-led administration.
Impact represents 60,000 workers, 50,000 of those are in the public sector, with many working for Irish Water.
General Secretary Shay Cody has said a vote should be held first and then allowances created for those who can not afford to pay for the service.
“We believe the safest next step is for there to be a constitutional amendment to protect the public water supply,” said Cody.
“If that was the first step, that would then allow for there to be a discussion about the amount of water that should be supplied to everybody in the country and Impact holds the view that beyond that amount then there should be fair charging regime, with exemptions for those who can’t afford it.”