Bay Area home prices climbed to a new high last month, according to a report by DataQuick, a real estate information service. Sales are staying at near-record levels, the result of strong demand and flat mortgage interest rates.

"We're watching carefully for any turn in the market. Right now we just don't see anything. Appreciation is pretty even across the different categories. There are really no changes in market mix; purchase and financing profiles are stable. Mortgage rates haven't gone up as they were expected to do, and demand appears to be strong," said Marshall Prentice, DataQuick president.

The information service reported the median price paid for a Bay Area home set a new record at $586,000. That was up 3.2 percent from $568,000 in March, and up 19.1 percent from $492,000 for April a year ago. The median price marks the halfway point at which half the homes sell for more and half sell for less.

Prices are rising at the fastest pace in four years and the appreciation rate in the Bay Area has now passed Southern California's for the first time in four years, according to DataQuick's statistics. The typical monthly mortgage payment that Bay Area buyers committed themselves to paying was $2,659 in April, an all-time high, up from a year ago when it was $2,237.

That's bad news for first-time homebuyers. While affordability conditions have improved at the national level for two consecutive quarters, the percentage of households in California able to afford a median-priced home decreased compared with the same period a year ago.

According to the California Association of Realtors Housing Affordability Index, the minimum household income needed to purchase a median-priced home at $490,000 in California in March is $115,910, based on an average effective mortgage interest rate of 5.81 percent and assuming a 20 percent down payment.

The numbers are troubling since first-time homebuyers are being locked out of homeownership because of the lack of affordable homes for sale, said Jim Hamilton, president of the association.

The Homebuyer Income Gap Index for California showed an increase of 44.9 percent during the first quarter of 2005 compared to the same time frame last year. The Bay Area had the highest income gap in the state at $92,930 where potential homebuyers had a median household income of $67,770 but needed qualifying income of $160,700 to purchase a median-priced home at $689,240.

The association's Homebuyer Income Gap Index is a quarterly analysis of the difference between the median household income and the qualifying income needed to purchase a median-priced, single-family home for the state and for select regions within the state. The index is calculated using the same assumptions for the Housing Affordability Index: a 20 percent down payment and a monthly payment for principal, interest, taxes and insurance that is no more than 30 percent of a household's income.

Information provided in this column is presented by the Realtor members of the Silicon Valley Association of Realtors at www.silvar.org. Send questions on any topic to gmeissner@silvar.org.