Some flood victims in Doncaster may never be able to return home with others facing an 18-month wait to go back, the town's mayor has said.
The mayor said the cost would run into many millions of pounds
Martin Winter said 700 "environmental refugees" in the Yorkshire town were still unable to return home.
He also said it was too early to say the eventual cost of the flooding, but predicted it would run into "millions of pounds".
About 300 homes in the Toll Bar area alone were affected by floods.
Announcing the start of the "recovery stage" on Friday, Mr Winter said: "It's a very early stage for us in Doncaster.
"It has been the biggest evacuation since the war, the biggest national disaster that Doncaster has dealt with in the last 60 years.
"It's been an incredibly difficult time for the people of Doncaster, who in some cases have lost everything they had."
Mr Winter said it was necessary to assess the situation fully before making a "knee-jerk" reaction about what help was needed.
He said many people in the flooded areas were "fiercely protective of their unity" and had expressed a desire to stay together as a community.
People made homeless were being moved from emergency rest centres to interim accommodation at hotels and colleges, he said.
Council housing, private sector housing, portable homes and caravans were also being considered as alternatives.
He said: "It may be six to 18 months for some people before we can actually get them back in their homes, if at all.
"We've got to do a full condition assessment to look at whether some of these houses are safe to get people back into."
Mr Winter said a large number of people did not have insurance and believed the government could not be expected to "bail out people who weren't insured".
He said it was a complicated issue because people with insurance might end up paying for it through higher premiums.