After a storm-swollen Potomac River rose over its banks and flooded Billie Gray's modest apartment in the Belle View neighborhood of Fairfax County, the retiree and her disabled partner were forced to spend six weeks as nomads, sleeping in rented motel rooms and on foldaway beds at a relative's.

Gray, 70, who suffers from lung disease, said she could not return to her home in the Belle View condominium community for weeks because mold affected the air in her building after flooding in the wake of Hurricane Isabel in September 2003.

Nearly two years later, however, Gray said she's suffering anew from the disaster she hoped had been put behind her. She and more than 140 fellow residents recently received what they described as threatening letters from the Federal Emergency Management Agency, demanding speedy repayment of money they had received as disaster relief from Uncle Sam.

Now Gray -- who is on a fixed income -- fears she might lose her home if she is forced to pay back the $3,643 the government is demanding.

"This is total insanity," she said. "I've been so upset . . . my blood pressure has shot sky-high."

FEMA sent letters to dozens of homeowners in the Belle View condominium complex, asking that they return about $200,000 of the $385,000 it awarded after the hurricane, according to agency spokeswoman Nicol Andrews. The requests ranged from about $500 to more than $3,000 per resident.

Andrews said that FEMA is trying to recoup money paid out for repairs. The majority of the homes in the 65-unit complex needed little repair because the first-floor units sit about five steps above ground level. But 17 basement units were destroyed.

FEMA typically has to recover 2 to 3 percent of the funds it disburses after an emergency because of duplication with insurance coverage, Andrews said.

"FEMA is limited in what we can do for people," she said. "If it's covered by an insurance policy, we cannot duplicate that benefit. We have an obligation to taxpayers. We don't allow people to double dip."

FEMA is in a dispute with the condominium association about who should be responsible for repairs on common laundry and storage areas that were harmed by floodwaters. FEMA said the association's bylaws say it should pay for the damage -- more than $6 million.

The condominium association's attorney and president did not return several telephone calls requesting comment.

Its general manager, Robert Schultz, said he had no comment on the dispute other than to say "the association is attempting to work with FEMA."

Government officials said privately that the association was woefully unprepared for floodwaters, even though Belle View sits in a flood plain. They could have gotten as much as $30 million in coverage through FEMA's flood insurance program, officials said.

When the flooding occurred, condominium board members said they were unaware that federal flood insurance was available and instead chose a $1.25 million insurance policy through a private insurer, Lloyds of London.

"I understand they're upset, but they should be upset with the condo association board, not FEMA," Andrews said.

After the hurricane, about 2,200 residents of the complex voted to borrow about $3 million to repair the laundry facilities and common areas not covered by their flood insurance policy. Residents had to cover the loan in addition to paying their condominium fees.

Ruth Heimburg, 53, a consultant and condominium resident, said she does not understand why she cannot use $3,800 that FEMA gave her to pay part of her special assessment. Since her home and heating system did not need major repair, FEMA wants $1,800 of that money returned.

"We used that money during the flood just to live," she said. "Why is FEMA now saying we committed some type of fraud? None of us did that intentionally. It's unconscionable that a federal relief agency would victimize people a second time."

After flooding from Hurricane Isabel, Jennifer Byrne sorted through Christmas supplies at Belle View condominiums.For insurance purposes, Belle View resident Kristin Neubauer made a photographic record of flood damage in 2003 to her six-month-old Saturn.