The Right 2 Water campaign says the Government should prove it is against the privatisation of the public water supply by putting the issue to a referendum.
Organiser Brendan Ogle said that "every politician", including Environment Minister Alan Kelly, is against privatising Irish Water - and the public also wants to ensure it is held by the public.
He says the "only thing" he wants to see happen is the abolition of Irish Water - and a protection of the right to water in the Constitution by way of a Referendum.
Ogle said that calling a vote would boost the Government's popularity.
"The only way to ensure that is to enshrine, as a responsibility of Government, that water should be managed in the public interest, in public ownership," he said.
"And if Alan Kelly is not for privatisation, the Government could make themselves popular overnight by doing this … [but] of course, they know they are part of a privatisation agenda."