Cash-strapped councils will find out in June how much they are expected to stump up towards improving defences along the Humber.
A 20-year programme of flood defence work on the Humber could be “higher or lower” than the £60m quoted earlier this month, the Environment Agency said.
Six councils including Hull, East Riding and North Lincolnshire will bear a proportion of the costs.
Humber Strategy manager Philip Winn said the £60m figure was based on a 2008 strategy, and was being revised following last December’s devastating tidal surge,
The surge, which flooded 1,100 homes on both sides of the river, had shown the areas where raising defences could be “sensibly” delayed and others where schemes would need to be brought forward, he said.
He said: “Having seen the effects of a very large flood it is helping us identify places which have pretty good protection or very good protection because they withstood the impact of what could be a once in a lifetime event.
“A conclusion in some places may be that we don’t need to raise the defences in the short term.”
Mr Winn said they wanted the future approach to managing flood risk “to be jointly agreed”.
Pressure is growing for defences to be raised on the River Ouse between Reedness and Swinefleet. One in thee houses in Reedness flooded in just 20 minutes. Mr Winn said: “It is a place that has clearly attracted a great deal of understandable attention. We would hope to be able to get a scheme underway as soon as possible.” Meanwhile the first of 82 cheques for £650 from a local appeal fund were landing on the doorsteps of flood victims in South Ferriby.