The Taoiseach Enda Kenny is insisting that water charges are affordable, saying 10 weeks' worth of water costs the same as around two pints.
Mr Kenny has again faced criticism in the Dáil for reports that the government may allow unpaid bills to be deducted from people's wages.
But he insists that many people who say they cannot afford the water charges are in fact able to do so.
It emerged last night that to secure it, a second registration with the Department of Social Protection will also be required in August before payment begins in September.
This will be on top of households being required to register with Irish Water.
The government had said that those wishing to get the €100 grant would have to register with Irish water before June 30th.
That still applies - but it has now been confirmed that to get the grant a second registration with the Department of Social Protection will also be required in August, before payment begins in September.
Minister Joan Burton spoke to Jonathan Healy on Lunchtime about the issue, stating that in order for the payment to go ahead from her department, they would need the correct details to register the payment, PPSN and a person's account details.
She also said that the matter has become clearer since Alan Kelly took over and she would have done things differently from Phil Hogan.
The environment minister said it was not unexpected that households will have to go through two registrations for the water conservation grant.
Alan Kelly told Live 95 this should not come as a surprise.