Running water is being restored to the first of 60,000 homes in the flood-hit Gloucester area, but many face several more days without supplies.
Forecasts of drier weather have eased the fears of flooding
Severn Trent hopes to restore supplies by Sunday to about 140,000 homes without tap water since a treatment plant flooded over a week ago.
Meanwhile, Environment Agency boss Baroness Young has defended bonuses paid to executives before the floods.
They deserved them and it would be "bizarre" to take them back, she said.
Also on Monday, in Hull, which saw about 6,500 homes flooded in June, council leader Carl Minns announced affected residents would receive a 25% discount on their council tax bills.
In another development the BBC learned that John Healey, the government minister with responsibility for floods recovery, is leaving the UK for a two-week holiday.
Mr Healey said the trip to France, which begins on Friday, was a family holiday which had been "booked for months".
The government said Communities Secretary Hazel Blears would lead co-ordination of the flood recovery work in his absence.
A statement from the Department for Communities and Local Government read: "We will continue to bring a sustained and determined focus led by senior members of government throughout the coming weeks. Any suggestion to the contrary is wrong."
Earlier, Severn Trent warned customers that restored water supplies in Gloucestershire would initially not be fit for drinking, even if boiled.
Gloucestershire's Chief Constable Tim Brain urged patience, adding: "Supplies are returning. You may just be a few hours away or just a few days away from total re-supply."
Fears of more flooding have faded and drier weather is forecast for this week.
The Army is stepping down from supplying bottled water in the affected area, having helped distribute two million litres each day since the crisis began.
Homes in Gloucester were the first to see supplies return and from Tuesday, about 27,000 homes in the Cheltenham area will also be gradually reconnected.
Andy Smith, director of water services at Severn Trent, said: "We cannot give exact timescales for how long this process will take as it is heavily dependant on demand levels.
"We are expecting high demand because, understandably, people who have been without water for more than a week will be eager to make use of a reconnected mains supply."
The company said where possible people should turn taps off which may have been left open when supplies were first lost.
HEALTH ADVICE ON WATER
Water from newly-restored supplies must not be drunk, even after boiling it
It must not be used for food preparation or cleaning dishes
It must not be used for making baby formula or baby feeds
Boiled bowser water is the best option for infant formula
It must not be used for cleaning teeth or making ice
Newly-restored water must only be used for sanitation purposes until further notice
Boil bowser water before use as a precaution
Floodwater must be avoided where possible and children must not play in it
If in contact with it, wash hands with soap, especially before food preparation and eating
If clearing up floodwater wear protective clothing and cover cuts and grazes
Source: Gloucestershire PCT
Newly restored water must not be used for preparing food, making ice or brushing teeth, it added.
It should also not be used to bathe young children, in case they swallow it.
David Wickens, from Severn Trent, said it would take several days for water to be declared safe.
"We have added extra chlorine so you'll probably get a smell of chlorine and that's all part of the process, but what we need to do next is to go round and take samples from actual customers' taps so that we can then test the quality of the water."
Severn Trent warned customers to be wary of bogus officials, and if in doubt call 0800 783 4444 to check.
Environment Agency chief executive Baroness Young, who herself received a £24,000 bonus, spoke about the payments to her staff after Gloucestershire residents said the money should be handed to flood victims instead.
In total nine EA executives, including the director of water management, received awards averaging 10% of their salaries.
Baroness Young said: "The performance-related element of this pay was agreed with staff in April or May and then confirmed to most of them in their June pay long before any flooding took place.
"It would be bizarre to give up on staff who have performed exceptionally well throughout the year and say to them 'I'm terribly sorry but because the weather has been bad we are going to take this away from you'."
The EA now has just one standard flood warning - for the river Severn from Tewkesbury to upstream of Gloucester, including Deerhurst and Ashleworth.
Communities Secretary Hazel Blears said it was important local and national authorities kept those affected "in our minds" in the months ahead.
"What's really important for government now is that we do the clean-up but that we also stay in touch with these people."
Insurance companies are facing payouts of £2.5bn for flood damage.
The government is seeking EU funding to help with the cost of the clear-up in flood-hit Yorkshire, Oxfordshire, Gloucestershire and Worcestershire.
Environment Agency floodline: 0845 988 1188
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