Households who have not yet registered with Irish Water have until midnight tonight to submit their details.
However they will still be able to avail of the €100 water conservation grant if they miss the deadline.
The Department of the Environment confirmed that there is no deadline in place for households to apply for the €100 euro grant.
Irish Water says 1.1 million households have registered with them so far – almost 80 percent of whom are customers of Irish Water.
That means 58 percent of the total customer base have registered.
Irish Water says homeowners will be charged the default rate of €260 euro, if they don't register.
Households with two adults, who take water in, and require waste water to be taken out – will face the maximum charge in April, whether they register or not.
