WASHINGTON (Reuters) - Sales of new U.S. homes fell 16.6percent in January and prices were little changed as the numberof new homes on the market decreased slightly, according to agovernment report on Wednesday showing some weakness in theunsteady housing sector.

The monthly decline was the sharpest in 13 years, since a23.8 percent drop-off in January 1994.

Freddie Mac, the second biggest buyer of U.S. mortgages, plans to toughen its standards and stop buying certain types of risky loans that have been linked to a high number of defaults.

This is latest indication of rising concern about problems in the subprime mortgage market, which caters to borrowers who are unable to qualify to buy a house with a conventional loan.

A six-year run of double-digit increases in Fairfax County home assessments came to abrupt end today, as notices mailed to taxpayers showed that their properties have lost value for the first time since 1998.

The good news for county households is that property tax bills, which have increased 47 percent since 2001, are also likely to show a real, if modest, decline. Under the budget proposed today by County Executive Anthony H. Griffin, the owner of a home worth $542,744 — now the mean assessed value of residential property in Fairfax — will pay $4,830 this year, $16 less than in 2006.

The “Supersize Me” era of home building may be coming to an end after a three-decade run.

The size of the average new home swelled by about 50 percent from 1973 to 2006, but this trend toward expansion will probably be ending in the next decade, according to an elite panel of 135 builders, architects and designers surveyed by the National Association of Home Builders recently.

New legislation on Capitol Hill seeks to curb an increasingly popular mortgage practice: providing home loans to applicants using their Individual Taxpayer Identification Numbers (ITIN), in lieu of Social Security numbers.

ITINs are issued by the Internal Revenue Service to immigrant workers who do not qualify for Social Security numbers for use when they report their income and pay federal taxes.

The four-bedroom brick Colonial was nice, but if her real estate agent hadn’t accidentally locked the keys inside six years ago, Sarah Mayhew might have missed the property’s extra selling point out back.

While the agent waited for the locksmith, Mayhew, an avid bird watcher, sat on the rear deck. A pair of red-shouldered hawks circled overhead, absorbed in a courtship ritual. Looking through the tree line, Mayhew had a view of Woodglen Lake, part of Fairfax County’s water-quality management program.

A hundred years ago, most Americans shared small living quarters with only a few rooms, and family members were constantly interacting with one another. This was still true at mid-century when millions of families moved out of the cities into single-family houses during the great suburban migration that followed World War II.

Though these new suburban houses had as many as five or six rooms, they were still small, and everyone was still within “talking distance” of each other. Most families had only one phone that was invariably located in a central public spot, so everybody in the household knew the weekend plans of the teenagers. There was only one bathroom, so the household also had plenty of contact in the morning before everyone hit the road to school and work.

Finding affordable housing is a daily challenge for the Rev. Mary Sulerud, a recruiting officer for the Episcopal Diocese of Washington.

Like many longtime Washington area residents, Sulerud bought her home in 1990, when prices were lower. But she lives the challenge every day at work, where she helps find homes for newly hired rectors and other officials of the diocese’s 93 churches and 20 schools. The diocese employs almost 200 members of the clergy, including about 14 newcomers — new rectors and the soon-to-be ordained — who need roofs over their heads.

Is a blowout taking shape in the impaired-credit mortgage market? Could lax underwriting standards during the housing boom years — no verification of applicants’ incomes or assets, low or no down payments, and big mortgages to people already saddled with heavy consumer debt — finally be coming home to roost?

The omens are unmistakable:

Q: I want to buy a house that my parents own. It has a mortgage of $250,000 and has been appraised for $499,000. My parents want $200,000 out of it. Should I ask them to refinance and get the money they want, then just arrange to put the house in my name? Or should I buy the house and give them the money?

I want to put an addition on the property and would like to have money to do this without stressing out financially.