Home prices fell in 80 percent of US cities in the third quarter, a record triggered by distressed foreclosure sales across the country.

The median price of a US home fell 9 percent in the third quarter from a year earlier and distressed sales accounted for at least a third of all transactions, the Chicago-based National Association of Realtors said today. The price fell in 120 U.S. metropolitan areas, rose in 28 and was unchanged in four, a record for the study, which began in 1979. US sales of single-family houses and condominiums rose to 5.04 million at a seasonally adjusted annual rate, up 2.6 percent from the second quarter.

NAR President Charles McMillan, a broker with Coldwell Banker Residential Brokerage in Dallas-Fort Worth, said price comparisons in many areas are like apples and oranges. “A very large proportion of distressed home sales are taking place at discounted prices compared to more normal conditions a year ago,” McMillan said. “It’s very challenging to understand proper valuation, given the differences between distressed sales and a larger share of traditional homes in sound condition. Under these circumstances, it’s extremely important for consumers to be armed with the professional expertise Realtors offer.”

Distressed sales – foreclosures and short sales – accounted for 35 to 40 percent of transactions in the third quarter, pulling down the national median existing single-family price to $200,500, which is 9.0 percent lower than the third quarter of 2007. A year ago, when there were significantly fewer distressed transactions, the median price was $220,300. The median price is where half of the homes sold for more and half sold for less.

Total state existing-home sales, including single-family and condo, were at a seasonally adjusted annual rate² of 5.04 million units in the third quarter, up 2.6 percent from 4.91 million units in the second quarter, but remain 7.7 percent below the 5.46 million-unit pace in the third quarter of 2007.

Lawrence Yun, NAR chief economist, said conditions continue to range widely. “A pattern of sharply higher sales in areas with large price declines is well established,” Yun said. “Affordability conditions have consistently been a major factor in driving sales. Historically during recessions, buyers have responded to incentives and it’s important for government to keep that in the forefront of stimulus decisions.”

According to Freddie Mac, the national average commitment rate on a 30-year conventional fixed-rate mortgage rose to 6.32 percent in the third quarter from 6.09 percent in the second quarter; the rate was 6.55 percent in the third quarter of 2007. Last week, Freddie Mac reported the 30-year fixed fell to 6.14 percent.

The largest sales gain during the third quarter was in Arizona, up 28.3 percent from the second quarter, followed by California which rose 28.1 percent and Nevada, up 26.2 percent.

The steepest declines in single-family home prices in the third quarter were in three California markets: the Riverside-San Bernardino-Ontario area, where the median price of $227,200 dropped 39.4 percent from a year ago, followed by Sacramento-Arden-Arcade-Roseville at $212,000, down 36.8 percent from the third quarter of 2007, and San Diego-Carlsbad-San Marcos, where the price dropped 36.0 percent to $377,300. “These areas have seen some of the strongest sales gains with some reports of multiple bidding,” Yun said.

The largest single-family home price increase in the third quarter was in the Elmira, N.Y., area, where the median price of $105,000 rose 12.5 percent from a year ago. Next was Decatur, Ill., at $93,400, up 8.7 percent from the third quarter of 2007, followed by the Bloomington-Normal, Ill., area, where the third-quarter median price increased 8.1 percent to $168,400.

The typical seller purchased their home six years ago and is experiencing net equity gains. The national increase in value since the third quarter of 2002 is 18.3 percent, which is a median gain of $31,000. Even with the current downward price distortion, 90 percent of metro areas are showing six-year price gains.

Median third-quarter metro area single-family home prices ranged from an affordable $65,800 in the Saginaw-Saginaw Township North area of Michigan to $650,000 in the San Jose-Sunnyvale-Santa Clara area of California. The second most expensive area was San Francisco-Oakland-Fremont, at $615,700, followed by Honolulu at $615,000.

Other affordable markets include the Youngstown-Warren-Boardman area of Ohio and Pennsylvania at $74,300, and South Bend-Mishawaka, Ind., at $88,000.

In the condo sector, metro area condominium and cooperative prices – covering changes in 57 metro areas – showed the national median existing-condo price was $210,800 in the third quarter, down 7.1 percent from $227,000 in the third quarter of 2007. Sixteen metros showed annual increases in the median condo price and 41 areas had price declines.

The strongest condo price increases were in the Dallas-Fort Worth-Arlington area, where the third quarter price of $149,900 rose 11.1 percent from a year earlier, followed by Bismarck, N.D., at $148,000, up 11.0 percent, and the Houston-Baytown-Sugar Land area, where the median condo price of $134,100 rose 8.1 percent from the third quarter of 2007.

Metro area median existing-condo prices in the third quarter ranged from $112,600 in the Greensboro-High Point, N.C., area to $456,300 in the San Francisco-Oakland-Fremont area. The second most expensive condo market reported was the New York-Wayne-White Plains area of New York and New Jersey at $324,000, followed by Honolulu at $322,000.

Other affordable condo markets include the Indianapolis area at $113,500 and the Cincinnati-Middletown area of Ohio, Kentucky and Indiana, at $117,300 in the third quarter.

Regionally, existing-home sales in the West rose 13.1 percent in the third quarter to an annual rate of 1.15 million and are 12.4 percent above a year ago.

The median existing single-family home price in the West was $266,300 in the third quarter, which is 21.4 percent below the third quarter of 2007. The only reported metro price increase in the West was in Farmington, N.M., at $193,600, up 1.7 percent from a year ago.

In the Midwest, existing-home sales rose 2.7 percent in the third quarter to a pace of 1.15 million but remain 10.6 percent below a year ago.

The median existing single-family home price in the Midwest declined 5.5 percent to $159,900 in the third quarter from the same period in 2007. After Decatur and Bloomington-Normal, the next strongest metro price increase in the Midwest was in the Wichita, Kan., area, where the median price of $125,300 was 5.5 percent higher than a year ago, followed by Champaign-Urbana, Ill., at $146,400, up 2.7 percent.

In the South, existing-home sales slipped 1.4 percent in the third quarter to an annual rate of 1.87 million and are 13.8 percent lower than the same period in 2007.

The median existing single-family home price in the South was $174,200 in the third quarter, down 3.7 percent from a year earlier. The strongest price increase in the South was in the Tulsa, Okla., area, at $139,800, up 5.1 percent from a year ago, followed by Amarillo, Texas, with a 4.2 percent gain to $128,300, and the New Orleans-Metairie-Kenner area of Louisiana at $166,800, up 4.1 percent.

In the Northeast, existing-home sales declined 1.6 percent in the third quarter to a level of 863,000 units and are 11.7 percent below a year ago.

The median existing single-family home price in the Northeast fell 6.5 percent to $267,700 in the third quarter from the same period in 2007. After Elmira, the strongest price increase in the Northeast was in the Trenton-Ewing, N.J., area, at $342,500, up 4.2 percent from the third quarter of 2007, followed by Buffalo-Niagara Falls, N.Y., with a median price of $114,200, up 3.0 percent.

Data tables for both metro area home prices and state existing-home sales are available here.