Thousands of homes have no running water after thawing temperatures have caused burst pipes.
The bad weather has caused problems with mains water supply across the UK and Ireland.
Around 12,000 people in London were without water on Sunday evening, Thames Water said.
Bottled water stations were opened and a number of schools said they would be forced to close on Monday.
Temperatures rose above freezing over the weekend after the Beast from the East and Storm Emma brought snow and ice to the UK.
The mercury is predicted to hit 11C in London on Monday but weather warnings for snow and ice are still in place for parts of north England, Northern Ireland and Scotland.
Trains in the UK were disrupted over the weekend and National Rail warned passengers to check services before travelling.
The Environment Agency said there was a risk of flooding from surging water levels due to snow melt as temperatures started to rise on Sunday.
Three flood warnings were in force, two in north-east England and another in Dorset, because of high tides.
An urgent appeal for blood donors has been issued by the NHS after stocks were depleted during the bad weather.
Orange and yellow alerts for snow and ice are still in place across Ireland until midday on Monday.
The weather will continue to warm up and any snow will be confined to hills and mountains by the end of the day, the Met Office said.
Forecaster Mark Wilson said: "There will be a noticeable change in the weather, it will be less cold and there will be less snow and ice.
"We are now going to see slightly less cold and milder weather, by Monday afternoon the temperature could be in double figures.
"There is a snow and ice warning for most of Scotland, through the day the snow will be restricted to the higher ground."
He added: "We can get these quite abrupt change in temperatures because of a change in wind direction.
"From Monday there will be a more southerly flow with milder conditions."