A small number of water companies were responsible for an 11 per cent overall increase in complaints last year, the Consumer Council for Water said.
Problems with new billing systems led to a 155 per cent increase in complaints to Southern Water and a 56 per cent increase to Anglian Water, the watchdog said. South East Water saw complaints rise by 55 per cent, on top of already high complaint figures, it added.
The council looked at the total number of complaints to water companies between April 2007 and April 2008. Southern, South East and South West had the highest number of complaints per 10,000 customers.
Complaints to Severn Trent Water fell by a third. Other companies continued to receive relatively few complaints, including Yorkshire, Northumbrian, Portsmouth and Hartlepool.
Dame Yve Buckland, chairman of the council, said: "It is very disappointing that a few water companies are responsible for the overall rise in complaints."