Northern Ireland Water's charges to non-domestic consumers will fall by an average of 6% below inflation in each of the next two years, it has been revealed.
Around £324 million will be invested on priority infrastructure improvements, the Utility Regulator said.
The watchdog has published its final determination on prices to be charged by publicly-owned NI Water to businesses and other organisations like churches for 2013-15.
Regulator chief executive Shane Lynch said: "Our determination challenges NI Water to deliver better value for its customers, requiring it to reduce its operating costs further while improving the service to its consumers. Northern Ireland's water industry can be as efficient and provide as good a service as anywhere in the world."
He said NI Water has made strides towards this goal in delivering earlier price control measures and the next one for 2013-15 sought to continue that work.
Water charges will not be charged to domestic consumers over the next two years following an Executive decision.
Key features of the determination include lower charges for consumers, falling by an overall average of 6% below inflation in each of the next two years.
There will also be around £324m invested on prioritised and targeted areas to deliver specified infrastructure improvements. There should be an improvement in overall performance at NI Water, narrowing the gap between the company and its average counterpart in Great Britain.
There will be a more efficient company, delivering a further 5% per year efficiency to reduce the 38% gap while concurrently improving services.
A spokesman for NI Water said: "In shaping our plan we have worked with the Utility Regulator and our stakeholders to propose a balanced way forward, allowing us to continue to improve the service to customers today and to invest to safeguard services for future customers."