The Environment Agency has said it is concerned about the prolonged nature of the heavy rain which has battered Gloucestershire this week.
The warning comes as the county is experiencing a further deluge of heavy rain, with the Met Office saying it will last until Sunday morning.
The bad weather brings further risks of flooding, with rivers already badly swollen and fields saturated.
Flood warnings remain in place for rivers including the Severn and Frome.
'Nowhere to go'
David Throup from, the agency, said: "We need to be prepared for it because the water has nowhere to go now.
"I suspect first of all it'll come on to the roads, we'll get a lot of surface water flooding again but at least it's during the quieter period.
"Then the rivers are going to start reacting, first the small ones and now the River Severn is beginning to kick in because it's more than bank full."
He said the agency had used Friday's rain respite ensuring flood defences were working well and clearing watercourses.
Gloucestershire County Council said it was prepared to respond to any further flooding on the county's roads.
It added its highways workers were ready to respond to any emergency calls.
They have also been clearing gullies and pumping water from the roads at hotspots around the county.
Jason Humm, area highway manager, said: "Since the severe flooding in 2007, a lot of work has been done to improve our drainage systems, which are now in good condition and given the current levels of rainfall are performing well."