Caldor Inc., which operates 79 discount stores, primarily in the northeast, is eyeing a major move into the Washington market, a top company official says.

"Washington is attractive to Caldor stores," said Joseph J. Schumm Jr., vice president, secretary and corporate counsel for Associated Dry Goods Corp., Caldor's parent company, which also operates Lord & Taylor, its second largest subsidiary. "I imagine they would want to move into that area, but we're a little vague as to when."

The comments followed the announcement last week that Associated is shutting down all five of its Baltimore Stewart & Co. stores and replacing them with Caldors next year as part of a major push south into the middle-Atlantic region.

Associated already operates four Lord & Taylor stores, which emphasize apparel, in the Washington area and Schumm said the Caldor presence in Washington would complement Lord & Taylor's visibility. He also said that landlords of the Washington and Baltimore area sites of Woolco, the discounter which is going out of business, have contacted Associated about the possibility of Caldor moving into those generally stand-alone facilities.

Stewart & Co., with area sales of about $45 million, had been unprofitable in the Baltimore market, lacking a clear identity, according to analysts.

The Stewart closings "mean greater profitability because they are getting rid of the overhead of a very unprofitable operation," said Walter F. Loeb, vice president and retail analyst at Morgan Stanley & Co. Inc. "It also gives Caldor a completely new window into Baltimore, a market without strong competition in its type of merchandise.

Associated labels Caldor as an "upscale discount department store," concentrating on so-called "hard goods," like electrical appliances. About 70 percent of Caldor sales are in hard goods, Schumm said, in contrast with Lord & Taylor, which sells virtually no hard goods.

There is little doubt in retailing circles that the Caldor push into Maryland will ultimately lead to an expansion program broader than just the five-store introduction. With various discount failures in recent years, like those of Woolco and Korvette's, Associated's market strategists see an opening for discounters in the relatively staid Baltimore market.

Since Associated bought Caldor for $313 million last year, it has become the company's largest division, with 1982 sales projected at between $850 million and $900 million. Only recently, Caldor has stepped up its presence in New Jersey, opening four stores there last year and another four this year. Those facilities were the company's first outside New York, Connecticut, Massachusetts and New Hampshire.

The Stewart closings will leave 725 full-time and 400 regular part-time employes in the Baltimore area without jobs when the stores shut down in March. Schumm said the company would do "whatever we can" to find positions at the new stores for Stewart employes. Associated reported 1981 sales of $2.75 billion and profits of $69 million. This year, the company showed sales of $2.34 billion for the first nine months of the year, up 37 percent over the same period last year.