A new wave of distressed home sales is rippling, more quietly this time, through American cities and suburbs.

Its unsettling effects are playing out here in Manassas, along Brewer Creek Place, a modest, horseshoe-shaped street lined with 98 brick townhouses. Several years after the U.S. foreclosure crisis erupted, the U-Hauls are back.

The last time, banks seized nearly every fourth house on the street through foreclosure. This time, homeowners are going another route: a short sale.

"I love this house, but I just have to leave," said Leanna Harris, 27, the owner of a corner unit that used to be the builder's model, with a stone path in the yard and a gourmet kitchen. "I'm at peace with it now."

The original owner bought the home for $400,714 in 2006; Harris and her husband, both bartenders, paid what seemed to be a bargain price, $289,000, in 2008. But they have fallen behind on their mortgage payments, in part because her husband was out of work. Now they have a $246,000 offer for the home, and the balance on their mortgage is more than that. They want to accept the offer. All they need is their bank's okay.

That kind of deal is called a short sale, and it's sweeping the country. In these deals, a lender allows a troubled borrower to sell a home for less than what's owed on the mortgage.

Completed short sales have more than tripled since 2008, and 400,000 of these deals are projected to close this year, according to mortgage research firm CoreLogic. The giant mortgage financier Fannie Mae approved short sales on 36,534 home loans it owned in the first half of the year, nearly triple the number in 2007 and 2008 combined. Freddie Mac, its sister company, approved 22,117 in the first half of 2010, up from a mere 94 in the first half of 2007.

Distressed homeowners are being drawn to short sales in large part because they can help protect a borrower's credit rating and thus the chance of buying another home later on.

"I worked hard for a long time to keep my credit score close to perfect, and I know a foreclosure would be much worse for my credit than a short sale," said Harris, who listed her Brewer Creek Place home as a short sale about a month ago. "If there's a chance we can avoid foreclosure, we'd rather do that."

In a short sale, homeowners must get the go-ahead from the mortgage lender. Sometimes that happens before the property is put on the market, and other times before the deal closes.

In some areas of the country, including the Washington region, lenders can later pursue borrowers for the difference between the proceeds collected from the short sale and the amount owed on the mortgage, also called a deficiency. But lenders say they only do so if they conclude the borrowers skipped out on a loan that they could afford.

For lenders, short sales are less expensive than foreclosures to handle and help ensure that homes transfer in good shape. And for the wider real estate market, these sales could help shore up the floor under housing values because homeowners - unlike with foreclosures - have a vested interest in getting the best price. That's because the higher the offer, the more likely the lender will approve the sale.