With a Garda helicopter flying over head, tens of thousands of people from all corners of the country marched from Parnell Square to Leinster House and back to O'Connell Street where Independent TD Clare Daly and People Before Profit TD Richard Boyd Barrett led a series of speeches.
"This day will go down in history as the day that the people decided to roar," said Clare Daly. "We are here in our tens of thousands to say water is a human right, based on need, not an ability to pay."
Waving placards saying 'Water tax will sink households', the crowds spent more than three hours marching around the city centre, chanting such lines as: "Kenny in your ivory tower, this is called people power!"
Speaking outside the Dail, grandparents Eileen and Joseph McDermott, both 77, from Coolock on Dublin's northside, summed up the mood of the crowd, saying water charges were a tax too far for hard-pressed householders financially crippled by years of austerity.
"We've been paying for a house for 45 years and now they are putting these charges on us. It's not acceptable. We have 12 children and 21 grandchildren and we're here for them," Eileen told the Sunday Independent.
The march was organised by the Anti Austerity Alliance (AAA) whose candidate, Socialist MEP Paul Murphy, took a seat in yesterday's Dublin South-West by-election, which was described as "a referendum on water charges" by Labour Party TD Eamonn Maloney.
The Anti Austerity Alliance's Galway spokesperson, Sean Byrne, later claimed that up to 100,000 people took part in the march.
"This is the biggest protest I've ever seen and the Government can't ignore us," he told the Sunday Independent. "There are about 100,000 people here - and we're only getting started."
During the concluding speeches at the GPO, Richard Boyd Barrett urged the protesters to "send selfies" at the event to Labour leader Joan Burton and said that more protests against the introduction of the charges will take place next month.
"Go back to your communities and unite and come together on a local day of protests on November 1 to beat the tax," he said.
Afterwards Clare Daly told the Sunday Independent that the sheer size of the protest will "be a huge confidence killer for the Government".