Emergency services are fighting to prevent the flooding of a major electricity substation on the outskirts of the city of Gloucester.
Water supplies in parts of the city have dried up, after a major pumping station was shut down earlier today.
Treated water supplies to Cheltenham, Tewkesbury and the surrounding villages are expected to run out later.
Britain's Environment Secretary Hilary Benn has defended the government's response to the widespread flooding hitting the country.
Large areas of Worcestershire, Gloucestershire and Warwickshire are still under water.
Tim Brain, chief constable of Gloucestershire police, has appealed for the public to remain calm.
Elsewhere, the Army has been called into Upton-on-Severn in Worcestershire, to bring food and water to the town, which is virtually cut off by rising flood water.
More than 1,000 people are thought to be trapped inside Upton, where the situation is said to be worsening.
Flood warnings are also in place in the east of England, including parts of London.
Up to 80,000 households and businesses in Sutton are being advised to boil tap water before drinking it because of the leaking of rain water into a tank, which had gone out to customers.
The Environment Agency chief executive Baroness Young has said €1.5bn a year is needed to prevent future flooding.
