Heavy rain in drought areas leads to flood warnings
The Environment Agency has five flood warnings in place in south-west England, a region currently in drought.
It said flooding was expected on parts of the Middle Stour, Doniford Stream, River Clyst, River Axe and River Taw.
Residents have been told to take "immediate action" to protect themselves and their property.
Flood alerts were in place in 42 areas of England and there was one flood warning and four flood alerts in northern and eastern Scotland.
Some areas saw up to 50mm (2in) of rain overnight and on Wednesday morning.
Showers are predicted across the whole of the UK for the rest of the week.
Southern England and Wales saw heavy rain earlier in the day, with downpours affecting the north of England and eastern Scotland as Thursday progresses.
The warnings of torrential rain and flooding come as parts of England suffer one of the worst droughts since records began.
End Quote Trevor Bishop Environment Agency
It won't reach down far enough to top up groundwater, which is what we really need”
The South West, South East, East Anglia, Midlands and parts of Yorkshire have recently been given official drought status.
And the nation has just experienced one of the driest and sunniest months of March it has ever had.'Flash floods'
Weather experts say the heavy April rain is welcome for crops and plants across the country.
However, they warn that - after 18 months of dry weather - only prolonged periods of rain will be able to replenish moisture deep in the soil.
Trevor Bishop, head of water resources at the Environment Agency, said: "It's going to take more than a week or two of rain to undo the effects of nearly two years of below-average rainfall.
"The recent rain is good for farmers and gardeners, and the cool temperatures ease the pressure on fish and wildlife in rivers.
"But with dry soils most of the rain will be soaked up - or, worse still, run off quickly if the surface is compacted, causing flash floods."
The rain would not "reach down far enough to top up groundwater," he added, "which is what we really need".
South West Water - which supplies Cornwall, Devon, and small areas of Dorset and Somerset - also welcomed the rain but said they had not been planning a hosepipe ban.
It said: "The public water supplies remain in a good position because we are not reliant on groundwater supplies."
"Although there has been an environmental dry spell, our total reservoir storage is at 85% - which is good."
Nevertheless, the Department for Environment, Food and Rural Affairs underlined the "pressure" on some water reserves, urging people to remain aware.
It said: "While we welcome the rain we have received over the past week we cannot be complacent and still need everyone to save water where they can."
Meanwhile, Scotland - an area not hit by drought - is expected to see heavy rain with a potential risk of flooding this week, and warnings that snow-melt could increase surface water next week.
Commenting on rainfall across the country, a spokeswoman for the Met office said: "There is no real end in sight to this unsettled period of weather.
"We'll certainly see showers across the country in the next seven days and longer forecasts suggest it will continue through much of May."
She added the showers would be broken by occasional sunny spells with average temperatures of between 11 and 13C.