Hundreds of mobile water dispensers are in place across Gloucestershire and millions of bottles of water are being distributed after the recent floods.
Bottles of drinking water are being delivered 24/7
Some 350,000 people, mainly in the Gloucester, Cheltenham and Tewkesbury areas, are without fresh water after the flooding of a treatment centre.
It could take up to two weeks to fully restore supplies.
The Environment Secretary said he had offered help to Severn Trent Water to bring supplies on line sooner.
Work is already under way to dry out the Mythe treatment works and get it back online.
Severn Trent water said on Tuesday evening that no further homes or businesses should lose their supplies if they had not already been cut off, with the exception of Painswick which is likely to lose mains water when its reservoir runs dry.
Up to 900 bowsers should be in place by Wednesday, pic by Andy Pryor
The water company said people to the south of Gloucester had been switched from Mythe to the Mitcheldean works, and that supplies would be maintained if people were careful.
Supplies in parts of Stroud, Randwick and Bussage have been reduced or stopped to help the situation elsewhere in the county.
Water in the Stonehouse area should return by the end of Tuesday, and residents supplied by Bristol Water are not affected by the shortages.
"I'm really, really worried - 350,000 people is hard to imagine, and amongst those are very vulnerable people," said Peter Bungard, chief executive of Gloucestershire County Council.
The army, based at Cheltenham Racecourse, is helping to get bottled water to supermarkets and distribution points across the county.
Long queues have been reported, but police have said there is enough water for all and residents should not panic.
Dr Tim Brain, Chief Constable of Gloucestershire Police, said: "We still have large areas of flooded fields and villages and isolated communities around the county - principally around the confluence of the Avon and Severn.
"We also still have this major issue of water supply to over half the county of Gloucestershire. So we're far from out of the worst of this at all."
Three severe flood warnings remain in force along the River Severn, although flood water was subsiding on Tuesday in Gloucester and Tewkesbury.