People in four areas of Gloucester now have no fresh water or electricity after a power cut affecting a large swathe of the western area of the city.
Castle Meads substation in Gloucester has been turned off due to the rising flood water affecting 48,000 homes.
Central Networks, which runs the power plant, says Gloucester, Cheltenham and parts of Herefordshire are affected.
Military personnel and fire equipment from around the country was brought in overnight to deal with the situation.
The overnight operation has saved a much bigger power station which is part of the national grid serving more than half a million homes.
"The water level within the protected areas which the Environment Agency set up and brought to us, it's actually going down, so we think we are definitely achieving our objective," said Chris Griffin of Gloucestershire Fire and Rescue, speaking in the early hours of Monday.
Military equipment was brought in to help the situation
"Go steady" water plea
Gloucestershire County Council has made an urgent appeal for builders' merchants to supply giant sandbags in an attempt to help stop the water getting into the electricity sub-stations on the outskirts of Gloucester.
On Sunday the Mythe pumping plant at Tewkesbury was swamped by the rising waters and 150,000 homes lost their water supply.
Bottled water and 600 water tanks have been brought into the county to bolster drinking water supplies but it could be days before the supplies are back on again.
Severn Trent is mobilising on two fronts to get bottled water to a number of centres and to bring more bowsers - large water tankers - to stricken areas.
Fraser Pithie from Severn Trent Water said: "Most of Gloucester city has no water now; Cheltenham still has got water but obviously its likely to lose its supply later today.
"We believe there's probably 20 hours worth of water left in Cheltenham and we are appealing to people in Cheltenham that if they go really steady they can perhaps make that 20 hours last even longer."
The county's Primary Care Trust is in talks with Severn Trent to ensure key health facilities such as hospitals and health centres continue to have access to clean water supplies.
People are being asked to be a good neighbour and check on the elderly and vulnerable to make sure they have access to bowser water or bottled water supplies.
Patients who have electric pressure mattresses at home are asked to contact their District Nursing Team for advice.
The PCT have moved to reassure the families of 27 patients who remain at Tewkesbury hospital that they have supplies of food and water.
Throughout the town GP surgeries have arranged for delivery of prescriptions for all patients. Those whose prescriptions are set to run out this week are asked to call their doctor.
BBC Radio Gloucestershire is running special programming with regular updates on the flooding.
It can be heard on 1413 MW, 104.7, 95.0, 95.8 FM, and online bbc.co.uk/gloucestershire