The waters have risen so far in parts of the country that familiar streets and landscapes have been left unrecognisable.
From kayakers setting out on a racecourse to deserted high streets, these five pictures show just how much damage has been wrought by back-to-back storms and weeks of downpours:
On Monday there were still two severe flood warnings in place in England alone, with 108 regular flood warnings and more than 200 flood alerts – and conditions are not expected to improve in the short term.
Rainfall is expected to continue hitting areas along the rivers Severn, Wye, Ouse and Trent, while two severe danger-to-life flood warnings were issued for Ironbridge and Shrewsbury in Shropshire, both along the Severn.
The torrents are contributing to record-high river levels and England has endured more than 141% of its average February rainfall so far, said the Environment Agency.
Authorities have warned that the country needs to prepare “for more frequent periods of extreme weather like this” as a result of climate change.
The Met Office has forecast a week of widespread showery weather, while a warning for ice covering Scotland, Northern Ireland and much of northern England remains in force until 10am on Tuesday.
Meanwhile, Downing Street defended prime minister Boris Johnson’s continued absence from flooded areas, with officials insisting it was important not to “distract” from the ongoing effort to deal with the problem.
The PM had been receiving “regular updates” about the situation while environment secretary George Eustice is “rightly” leading the government’s response, said No.10.
Caroline Douglass, director of incident management at the EA, said: “Flooding has a long-lasting and devastating impact on people’s lives.
“River levels remain high and communities along the river Severn, in particular Shrewsbury, Bewdley and Ironbridge, should be ready for potential flooding.
“Groundwater levels across parts of Dorset, Wiltshire, Hampshire and Sussex are continuing to rise and will lead to more flooding impacts later in the week.
“We have seen our third weekend of exceptional river levels and stormy weather; with the effects of climate change, we need to prepare for more frequent periods of extreme weather like this.
“People need to be aware of their flood risk, sign up to flood warnings, make a flood plan and not to drive or walk through flood water.”
A thousand staff a day have been working to operate flood defences, pumps, and clear debris since Storm Dennis and Storm Ciara swept across the UK in quick succession.
Nearly three and three-quarter miles of temporary flood barriers have been erected and flood defences have protected more than 25,000 properties, authorities said.