In spite of record house sales, there remain a surprising number of hard-to-sell "dogs" in today's Washington-area market.

Ironically, those houses are not old. In most cases they were built three to six years ago. Many are in developments in some of the most prestigious areas of the metropolitan area. And, according to many agents contacted, the sellers probably are young professionals who bought the homes for tax advantages.

But they have been poorly maintained, are filthy and often reflect ownership by people too tired, lazy or strapped to keep up their homes, agents say.

"I'm tired of kicking dirty underwear out of the way as I show houses," said one agent who has sold several million dollars in properties in Northern Virginia in recent months.

Her complaint about dirty underwear, dirty kitchens and filthy bathrooms was echoed by a surprising number of real estate agents in the Washington area.

The dirt, particularly personal items like underwear, is a real turnoff for potential buyers, making them feel as if they are intruding into the lives of the owners, explained Connie Jenkins, an agent in McLean.

Jenkins, like other agents, said she was reluctant to talk about such things but said she is tired of the dirt and mess she sees as an agent. The problems are especially apparent, she said, in homes in the $140,000 to $250,000 range where perhaps both adults work to make high house payments and are too busy with the social life that goes along with being young and professional in Washington to keep up with general maintenance and cleaning necessary to sell a home even in today's market.

"Anything that is presented properly and is in basic good shape is selling," according to Jean Paris of Shannon & Luchs' office in Fair Oaks. "The most common mistake is that they the seller do not get the house ready to resell."

Getting a house ready to sell means getting the seller's mind in order also, several agents said. Sometimes it means changing living habits. "Some people just don't see their own dirt," said Jewel Monroe, an agent in Fairfax.

"You would not believe what we see as agents. Housekeeping may not be the most important thing, but housekeeping translates as maintenance," said Charlotte O'Conner, a Property Associates agent.

Other agents agreed that dirt, grime and poor maintenance make a house hard to sell. Agent Jenkins this week showed 15 resale houses in Northern Virginia to a corporate client being transferred into this area. "Two of the 15 showed well. The rest were just plain dirty. The bathrooms were a mess. The beds were unmade. Dirty dishes were piled in the sink.

"For $150,000 they could at least expect a clean house," Jenkins said. She said she was especially disappointed with deterioration and lack of maintenance in what most see as the nearly new housing market.

Other agents agreed. Paris said reselling in this market is especially hard in areas where the same builder is still working and offering the same basic product new. This year a house that may be painted to the owner's taste and have fingerprints on the wall must compete with essentially the same thing being offered by the same builder with skylights and a jazzy bath, options that weren't available four or five years ago when the resale house was built.

Paris said that means those trying to resell have to do something to make their house attractive. "You can't compete with the builder."

The problems for resale of the nearly new homes may be intensified in the Washington suburbs in contrast with other parts of the country because of the building boom in residential housing this year. Many of those trying to sell houses they bought a few years ago are discovering that the same builder may now be developing an expansion of their neighborhood or a similar development just down the road. Agents pointed to cleanliness problems in all parts of the Washington area, in high-priced homes and in less expensive homes. Agents were careful not to go on record specifically naming neighborhoods, but several pointed to what they called a strange irony -- that homeowners in one development may be far better housekeepers than those in an adjacent development. "Often, it is those who bought the homes in the development with a slightly lower price tag that have worked to maintain and improve their homes," said one agent.

One reason for that may be that those with bigger mortgages may be suffering from cash-flow problems that lead to delayed maintenance and rule out the hiring of household help.

"It is amazing that they won't clean up when they get ready to sell," said Jenkins, who added that she is tired of the dirty houses listed on the computer. Several agents said it is "embarrassing" to show houses to clients when people have not bothered to clean them up.

"People walk in a spanking new house with a warranty, free of responsibility for what goes wrong" and are likely to choose that home over a three- to five-year-old home in the same area, said Tom Stevens, president of the Northern Virginia Board of Realtors. "It's the seller's responsibility to make sure the house is clean," he said. But it is also the agent's responsibility to tell the seller about problems.

"The best thing an agent can do is be up front and honest. Take them [the seller] out and show them the competition."

Some of those dirty resales now on the market may belong to people who are trying to see if they can take advantage of the present housing market in which houses are selling rapidly. "Maybe they just don't care whether it sells or not," said one agent. Other agents said they doubted much of that was going on because many listings indicate the seller has been transferred.

Grubby houses with dirty clothes spread out like a path leading to rooms where "lollipop-colored" carpets cover floors surrounded by dust-covered baseboards are not what agents like to show, said several gathered for an interview. "We can't sell them, so why should I show it?" asked another agent. Agents in Maryland and Virginia said buyers that are being transferred into Maryland or Virginia are willing to go into rental housing to wait for a new house rather than take a nearly new one that was not clean the first time they saw it.