Sales of existing homes eased 2.6 percent nationally in July compared with June, the National Association of Realtors reported yesterday, although they remained at near-record levels.

There were also more homes to buy, as the for-sale inventory rose to a 4.6-month supply, the highest level since 2003.

The national median price of all types of existing homes, the point at which half the homes cost more and half cost less, rose to $218,000, up 14.1 percent from a year ago.

"It's a one-month number and we need to know what the trends are, but we're seeing a slowing of sales that is preceding a slowing in prices," said Nicolas P. Retsinas, director of the Joint Center for Housing Studies at Harvard University. "Even so, it's a pretty robust market."

Sales of condominiums were off 5 percent, compared with a 2.3 percent decline for single-family houses.

In the South, the region that includes the Washington area, month-over-month sales were flat and prices moderated somewhat, rising to a median of $187,000, up 7.5 percent from July 2004.

The Realtors noted that the levels of sales activity remains high, with July marking the third-highest month of sales ever, after records in April and June. At this rate, 7.16 million existing homes are expected to change hands over the next 12 months.

"This is a big number any way you slice it, and housing is continuing to stimulate the overall economy," said David A. Lereah, chief economist for the Realtors, in a statement.

According to the Mortgage Bankers Association, which also released a housing market report yesterday, the soaring prices of the past few years have been an aberration.

Over the past 30 years, home prices have increased an average of 6 percent per year, so "prices have been increasing more quickly than is customary," the report said.

Douglas G. Duncan, chief economist for the Mortgage Bankers, said that recent modest sales declines such as those reported by the Realtors show the risks of a housing bubble are "far less dramatic than the hyperbole of recent months."

He said, though, that the drop-off in condominium sales bearing watching.

"We're starting to see some slowing on the condo side," Duncan said. In the report, his group's economists said that a sudden increase in supply of condo units could lead to price decreases.

"Buyers need to be mindful that historically condos have experienced a greater level of price volatility," the report said.

Fred Kendrick, a real estate broker with Coldwell Banker Residential Brokerage in Georgetown, said he believes the market has slowed because "so much is overpriced." He said many sellers continue to expect to receive the "20 percent to 30 percent appreciation that people were getting at the busiest months."

The number of homes sold in the District dropped 18 percent in July from June and was lower than in the same month in the three previous years, according to statistics Kendrick compiles based on information from the Greater Capital Area Association of Realtors. The inventory of available homes was 18 percent higher than it was one year earlier.

The market often slows a bit in the summer, cautioned JoAnne Poole, president of the Maryland Association of Realtors and a broker in the Coldwell Banker sales office in Glen Burnie. "I think we'll see a bit more decline in August," she said.

Sales of existing homes in July were the third-highest ever, a drop of 2.6 percent from the record set in June.