With rivers bursting their banks and groundwater brimming at the surface, the additional rainwater will put additional pressure on the underground sewers which are already full.
The firm, which operates more than 67,000 miles of sewers, has been struggling in some areas to cope with the additional water filling up its pipes.
More top news
Tuesday afternoon's weather for the west of the region
Tuesday afternoon's weather for the east of the region
A site in Brighton that a carpenter was working on before he fell, sustaining fatal injuries, was 'blatantly not safe' a court has heard.