By Madeleine Morris
BBC News, Washington
Janet Napolitano saw the effects of the flood for herself
The US homeland security secretary has been touring Nashville, which, along with other areas in the American South, was hit by flooding this week.
More than 30 people died as flood waters swept through the states of Tennessee, Mississippi and Kentucky, destroying homes and businesses.
Janet Napolitano said she expected government workers to be still cleaning up in six months time.
The cost of repairing the city is estimated to be at least $1.5bn.
The floodwaters that swept through Nashville last week didn't discriminate, ruining trailer homes, as well as the mansions of country music's elite.
Multi-award winning singer Keith Urban was just one artist who lost his stock of guitars to water damage.
More than 16,000 Tennessee residents have already registered for federal assistance.
But, as she toured Nashville on Saturday, the Homeland Security Secretary Janet Napolitano warned there were limits to what the government could do.
"There will be individuals who will be suffering financial damage and I'm not going to say we're going to guarantee everybody is going to be made whole," she said.
"We will do as much as we can in every possible way that we can."
As waters receded, volunteer cleanup efforts are gathering pace, with hundreds turning out on Saturday to provide food and shelter to those whose homes have been gutted.
Many Nashville residents had never considered protecting themselves against the risks of flooding.
"I just can't believe it. It's just so devastating. When I moved here I didn't even think about getting flood insurance," said one person.