US army engineers have finished draining New Orleans of floodwater, more than a month after the city was devastated by Hurricane Katrina.
President Bush has been criticised for the government's slow response
A spokesman said 250 billion gallons had been pumped out and all parts of the city were now accessible.
The announcement came as President George Bush visited New Orleans and other areas affected by the hurricane.
Nearly 1,200 people are known to have died in New Orleans and surrounding areas of Louisiana and Mississippi.
Eighty percent of New Orleans was flooded by Hurricane Katrina and some levees were breached a second time during Hurricane Rita.
Many areas remain uninhabitable, and a number of stores and businesses are still closed.
During the draining operation, army engineers used mobile pumps. The permanent pumping stations around New Orleans are gradually being brought back into service.
During his eighth visit to the southern coast since Katrina struck, President Bush had dinner and stayed overnight in New Orleans before travelling to parts of Mississippi and Louisiana.
He went to a newly opened school and then wore a tool belt as he hammered nails into boards at a housing project.
Flood defences were also battered by Hurricane Rita
The US president has been criticised for the government's slow response in the immediate aftermath of the disaster.
"If I didn't respond well enough, we're going to learn the lessons", he said.
The civil rights leader, Jesse Jackson, has criticised the Bush administration for being slow in allowing New Orleans residents to return to their homes, denying them potential jobs.
Opinion polls show that more than half the American public disapprove of his handling of the crisis.