The water company said the reduction is particularly noteworthy considering that retail price index (RPI) inflation is currently running just above 3 per cent.
It said metered customers will see a decrease in their combined water and sewerage bills of around 1.3 per cent, while unmeasured customers will see their combined bills fall by approximately 3.6 per cent.
NI Water attributed the fall to cost efficiencies made during the Price Control 2010 period.
The charges, approved by the Utility Regulator, have been welcomed by Consumer Council for Northern Ireland.
Antoinette McKeown, chief executive of the consumer group, said: “At a time when significant financial pressures continue to have an impact on businesses and farms, any reduction in prices is good news.”
McKeown encouraged customers to look at the Scheme of Charges, which sets out what NI Water will charge its customers for all its services, to ensure they are benefitting from any allowances that are available to them.