Repairs to the bulk of potholes left across County Durham over the winter are likely to cost at least £2.5m
More than £500,000 has already been spent on dealing with hundreds of potholes left by the worst winter weather to hit the area in 30 years.
Durham County Council said a further £2m would be needed to bring roads back to a safe standard.
The authority said it expected a programme of summer repairs to be completed by September.
Durham County Council's strategic highways manager, Dave Wilcox, said: "We have spent £500,000 between January and March alone making the worst-hit areas safe for motorists.
"It is now our intention to look at a structural patching programme for the rest of the summer to the tune of about £2m.
"We have been lucky enough to have been given £1m of that from the government and we are repriorotising our own finances to find the balance.
"We expect this programme to be finished by September."