The afflictions of these wounded buildings have forced major tenants like Morgan Stanley, J.P. Morgan, Oppenheimer & Company, Sullivan & Cromwell, Standard & Poor’s and The Daily News to either pursue short-term leases in alternative spaces or crowd into unaffected offices that they already lease in other parts of the city or region. Some businesses were assuming temporary quarters at the MetroTech Center in Brooklyn.

People unable to get back into residential buildings found themselves imposing still more on friends and relatives, or contemplating short-term sublets.

At 200 Water Street, a big apartment tower, residents were told on Sunday that the building would not be fully operational for at least two weeks, and perhaps much longer. They were advised to find interim housing elsewhere.

“Some of the buildings will clearly not be able to let people in, simply because of the damage to the equipment," said Steven Spinola, president of the Real Estate Board of New York. "I’ve heard that it could be a number of weeks in some cases."

A business leader briefed by the city and the utilities said that about 100 buildings south of Chambers Street would be opening and have electrical power but no steam, meaning they would have no heat or hot water. Other buildings with, or close to, flooded parking garages have a more serious problem. Most are older office and residential structures on the East River at the southern tip of Manhattan, and buildings on the western tip near the Hudson River.

Because cars and other vehicles were submerged, gasoline, oil and other chemicals poisoned the waters that entered the buildings. As a result, the buildings themselves will have to undergo special cleanups before people are allowed in. These cleanups could take weeks.

The large residential building at 2 Gold Street in the financial district has contaminated fuel oil in the basement, and the doorman and several residents said they had been told it would be at least a month before they could return.