Toilets that will cut water consumption by more than a quarter will be compulsory under proposed new building regulations.
Minister for the Environment Dick Roche said the "dual-flush" toilets will save hundreds of thousands of litres of water and so also save local authorities hundreds of thousands of euro every year.
Minister for Environment Dick Roche:
Mr Roche today published a consultation document on the proposed amendment of the national building regulations. Under the new rules, dual-flush toilets would be mandatory from January 1st, 2008.
"As our economy and population increases, so does the demand for water. Increased amounts of water are being extracted from various sources and then require treatment in order to make them fit for human consumption," Mr Roche said.
"We must cut back on drinking water demands on our natural resources of lakes, rivers, springs and wells. We must also cut back on the energy consumed in the treatment of water to make it drinkable and then use more than one third of it to flush toilets."
Many new homes and business premises are already fitted with dual-flush toilets.
The dual-flush cisterns have a mechanism that allows a six-litre maximum flush or a four-litre minimum flush. Current single-flush toilets use between six and nine litres per flush.
Mr Roche said: "I expect dual flush toilets to reduce treated water consumption by approximately 27 per cent, or at least 700 million litres of drinking water every year. This represents an annual saving of at least €700,000 per annum to local water service authorities.
"The estimated capital cost of a public water scheme producing 700 million litres per annum is estimated at between €2.8 million and € 3.4 million, at 2006 prices," the Minister said.
A public consultation process on the new regulation will take place until the end of January 2007.