A glass of tap water in a restaurant could cost a euro from next year, as Irish Water moves to increase commercial rates for businesses.

Restaurants are expected to pass some of the cost on to the consumer by charging for filtered tap water.

Adrian Cummins from the Restaurants' Association of Ireland told the Sunday Independent that it is only fair for businesses to charge as their own costs go up.

"Some people think it's carte blanche but we're not a public service - it's a business and people need to respect that," he told the paper.

He added however that charging for tap water will probably be done on a business by business basis.

The Consumers' Association of Ireland has warned a move away from free tap water as part of general service will 'indirectly backfire'.