The US government has issued guidelines on rebuilding thousands of homes and businesses in New Orleans, seven months after Hurricane Katrina hit.
Many feared New Orleans' poorest areas would have to be abandoned
Under the new federal advisories, many of the buildings will have to be raised up to three feet (0.9m) for residents to qualify for flood insurance.
The Bush administration also pledged an additional $2.5bn (£1.4bn) to replace flood walls and raise levees protecting 98% of the population in the region.
The funds must be approved by Congress.
"This will enable people to get on with their lives," said Donald Powell, the federal rebuilding co-ordinator.
Mr Powell declined to estimate how many homes would have to be raised but described the recommendations as good news, saying raising a house three feet was "not that dramatic".
The flood advisories detail how high the water might rise in areas of the city during an extreme event known as the "100-year flood", and how well the levees would protect residents.
The proposal also answers fears over whether flood rules might bar some of the city's poorest low-lying areas from reconstruction, such as the Lower Ninth Ward.
Many officials had feared that some areas of New Orleans would have to be abandoned, but under the new plans the entire city will be protected.
Residents say raising their houses will sharply increase repair costs
This "brings certainty to some uncertain issues along the greater New Orleans area", Mr Powell said.
'Spur in activity'
Property owners who ignore the guidelines risk losing government aid and could face higher flood insurance premiums.
The new building guidelines do not apply to existing houses, those that suffered 50% damage or homeowners who obtain permits before the rules come into effect.
Homeowner Timothy Riley, 44, said the guidelines would sharply increase the cost of repairing his home.
He said: "We'd have to tear our house down. There is no way we can jack the slab up to go any higher."
Jeb Bruneau, president of a neighbourhood association in the city's Lakeview area, was relieved that the recommendations had been released.
"This will spur activity unbelievably," he said. "A lot of people have been waiting for the advisory to come out so they would have direction.
"A lot of people are looking at this as progress," Mr Bruneau said.