Around 200 people attended an anti-water charges protest in Galway this evening.
The demonstration, organised by the recently formed Galway Right2Water group, was held in Eyre Square.
Campaigners told the crowd that the introduction of charges highlights Government "contempt" for those who are unemployed and on low incomes.
The move has been described as regressive and demonstrators were asked to mobilise to fight the introduction of charges.
One of those involved in the campaign, Dette McLoughlin, told the gathering that Galway was fighting back and would have activists across the city to oppose the installation of water meters and the presence of Irish Water vans on housing estates.
She called on people to stand together to oppose the charges.
Another protest took place at Irish Water's headquarters in Dublin today, where protesters returned water packs the company had sent out as part of the registration process.
Meanwhile, Minister for Finance Michael Noonan is to bring forward an amendment that will prevent ministers from claiming water charges as a deductible expense for a second home which they require for their official duties.
Under present legislation, a minister or minister of State whose official duties require him or her to have a second residence can claim an income tax deduction in respect of expenses to maintain that home.
Labour TD John Lyons has welcomed the decision, saying: "It goes without saying that no minister, junior minister or any other politician for that matter should be exempt from water charges, or should be treated more favourably in this regard than anybody else."
Mr Lyons added that he "can't imagine for one minute, that any minister would actually have claimed the exemption, but the clarity we now have in this regard, should put the matter to rest".
People who own a second home are liable to pay a charge of €125 on their non-primary residence.
From today, households and businesses will be charged for the water they use.
However, bills for water charges will not be sent out until January.
Irish Water has encouraged everyone to register and said there are arrangements being put in place to help people who cannot afford to pay.
Its spokeswoman Elizabeth Arnett said there is a range of options open to the company if people decided not to pay.
Speaking on RTÉ's Morning Ireland, she said the company would pursue any option open to it, including court action, if people with the means to pay their bills are refusing to do so.
Ms Arnett said the company also has authority to restrict flow to households, as a last resort.
However, there is no circumstance where people will have their service cut off entirely.