With days to go until the deadline, it's reported today that less than 1 in 10 septic tanks has been registered at a special lower cost, with Donegal returning one of the lowest percentage registration rates.
A reduced 5 euro fee is in place until the end of the month, before the full charge of 50 euro kicks in.
All tanks have to be registered by the start of next February.
There are over 497,000 tanks around the country, and so far, less than 46,000 have been registered.
According to new figures, Donegal has a registration rate of 6% so far, compared to 16% in Waterford it in Wicklow.