Households will need to register their septic tanks before February 2nd next or face the prospect of being fined up to €5,000.
The Government has announced new rules on septic tanks which homeowners will be obliged to make sure they are working properly and do not pollute water.
An inspection regime will begin next year, Environment Minister Phil Hogan said, adding it would cost households €5 to register their tank up to September 28th 2012, after which it would increase to €50.
There will be no charge for inspections.
The inspection regime is being introduced after the European Court of Justice ruled that Ireland was not doing enough to protect drinking water sources.
Mr Hogan said that in a small number of cases, septic tanks might have to be upgraded. Some financial assistance might be available, he added.
Registration will last for five years, and there will be no fee for second or subsequent registrations. Registration can be completed online at www.protectourwater.ie by credit or debit card, by post, or at local authority offices.