The National Weather Service has issued more than 500 flood alerts and warnings for England and Wales.
To the north in Scotland, nearly 50 warnings have been issued, but it's the southwest of England that has borne the brunt of the heavy rains.
Emergency services have been working around the clock, rescuing people trapped in their cars and homes.
One woman was found clinging to a tree overnight after being swept from a car near Barnstaple in the district of North Devon.
Emergency accommodations are being set up and tents have been given to some residents.
Helston in Cornwall and Braunton in Devon are among the worst hit communities, with flooding occurring on land that was already waterlogged.
Residents have been forced to wade or cycle through the water, with some opting for makeshift boats.
Some of the roads in the southwest are inaccessible due to flooding.
Heavy rain is in the forecast Sunday for Scotland and the southwest of England is in line for more of the same on Monday.