Northumbrian Water reported steady demand among domestic and industrial customers as it posted higher revenues and profits in the half year to 30 September.Pre-tax profits climbed to £151.3m from £139.3m on revenues that rose to £369.4m from £351.2m, but net debts were also higher, climbing to £2.266bn from £2.250 the previous year."Demand from both domestic and industrial customers has remained steady, with increases in measured water volumes," the company said.Northumbrian, which operates in the Northeast of England and in Essex and Suffolk, said highlights during the period included a 28% reduction in customer complaints and the continued expansion of a reservoir that will secure supplies for the Essex region, due to be completed in 2013.'The group continues to produce strong financial and operational results providing a platform from which to fulfil its regulatory and contractual obligations over the next five years,' said chief executive Heidi Mottram.