People have until midnight to register for Irish Water.
So far over a million people have signed up to the charges with over 835 thousand yet to give their details.
Protests took place this weekend against the bills.
Households who don't sign up face the maximum charge of 260 euro.
Those who register will receive the correct bill and are also eligible to apply for the 100 euro Water Conservation Grant.
The first bills will be sent out from April.
