More than 1.2 million households have now registered with Irish Water, with more than 130,000 doing so in the past month alone.
The utility company said its expected the rate of registrations to accelerate further in the coming weeks, as it prepares to issue its first bills next month.
Meanwhile, the Right2Water campaign said it expected tens of thousands of people to attend its national anti-water charges demonstration on Saturday.
There are three assembly points for the event in Dublin - Heuston Station, Connolly Station and Merrion Square at 1pm.
People Before Profit TD Richard Boyd-Barrett said the demonstration would send a strong message.
"There'll be a big rally at the top of O'Connell Street where there will be speakers an music - a message about the next step for the campaign," he said.
"[It will] say [the Government] haven’t done enough - we want these charges scrapped."