Some 350,000 households in Gloucestershire may be without running water for up to two weeks. What are the health implications?
Boiled bowser or boiled bottled water should be used for baby milk
The Health Protection Agency says the greatest health risk from flooding is the stress and desperation caused by a damp, damaged home.
The health risks of contact with flood water are very low, but losing a clean water supply - and in this case any water supply at all - can be serious.
The very old and the very young can easily become dehydrated, and infant formula milk needs to be made with very clean water as babies are at risk of infections such as gastroenteritis - a condition which itself causes dehydration.
Mini water tankers - or bowsers - are being installed across the county. While the water inside is of drinking quality when it first arrives at the site, experts recommend that as a precaution it is boiled before being consumed or used to wash food or brush teeth.
Boiling it kills any bacteria, parasites or viruses that may be lingering, and it can then be kept in containers in the fridge.
Bottled water is the other option, although there have been widespread reports of supermarkets rapidly selling out.
While the HPA was initially advising parents not to use bottled water, boiled or otherwise, when they make up infant milk on the grounds of its salt content, this advice has since been revised.
The agency now says that either boiled bowser or boiled bottled water should be used for feeds.
An alternative is to buy ready made cartons of formula. But if this is not an option and no electricity is available for a kettle, unboiled bottled water can be used, and as a last resort, unboiled bowser water.
For a baby, the risk of dehydration can be even more serious than the risks posed by unsterilised water.
Because dehydration is also a threat to older people, the Gloucestershire Constabulary is urging people 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".
Mervyn Kohler of Help the Aged stressed that the elderly were the least likely to be able to "elbow their way past others to get to the bottled water in the supermarkets".
"They are frail, and they really are at risk at a time like this, and it would be a terrible shame is we saw elderly people dying during this crisis because neighbours had not rallied round."
According to Gloucestershire PCT, key facilities such as hospitals and health centres currently have access to water supplies, and talks are continuing with Severn Trent Water to ensure this continues.
But the threat to the water supply is having a direct impact on treatment: radiotherapy sessions at the two main hospitals have been cancelled because of the large amount of water it takes to cool the equipment used.
All non-urgent operations and out-patient visits have also been cancelled, and dialysis patients diverted to hospitals outside the affected area.
Lack of water also means no supplies in the toilet.
Flood water can be used to flush the toilet although you will need to wash your hands with clean water afterwards as there is a small risk of infection from contaminated water.
However, the advice is: if you don't really need to flush the loo, don't. There are no health implications from not flushing after every visit.
But whether visiting the toilet or not, good hand hygiene is needed in a flood zone, and essential for anyone who is about to prepare or eat food.