The short-term effect will be improved cash flow and reduced borrowings and interest charges. However, investment in 1996 is likely to accelerate.
Analysts said the effect of rescheduling capital spending would be broadly neutral and the underlying performance of Northumbrian would not be affected.
In July, Ofwat, the water industry watchdog, announced an investment programme for Northumbrian of £658m for the five years to the year 2000.
But a Northumbrian spokesman said spending plans had changed after talks with the National Rivers Authority about meeting environmental objectives for sewage disposal.
The company said: "These processes have meant that NW's investment programme for 1995/96 will be lower than intended and lower than that assumed by Ofwat in the price review, with consequent short- term improvement in cash flow and reduced borrowing. "Itis anticipated that there will be an acceleration of investment in 1996/97. In recognition of this, NW has decided that prices to customers for 1995/96 should increase by less than the amount permitted."
Charges will rise by 4.62 per cent rather than the allowable increase under the price formula of 5.12 per cent.