You won't catch Bill Detwiler claiming this is going to be the greatest fall Washington retailers ever had. Nor will Ed Hoffman or Irwin Zazulia try to tell you their newest stores are instant successes, ringing up record volumes from the day they opened.

Between the national recession and the local sag in sales that seems to happen every time there's a presidential election, Washington's master merchants are facing their toughest season in years.

But the men who head Garfinckel's, Woodward & Lothrop and Hecht's are not a troubled trio. The fall season aside, the District's three biggest stores are dividng into a decade of expansion, innovation and excitement.

Forget about boutiques -- the era of The Big Store is back. Ignore the interlopers from New York, California -- Texas the hometown boys are making good. Don't worry about the next five months -- it's the next five years that matter.

Five years from now, Garfinckel's will be doing twice as much business as today and making twice as much profit, says Detwiler, its president. After not opening a new store since 1973, Garfinckel's is bringing in two this month -- at Annapolis and Fair Oaks -- plus another next year and probably a couple more the year after that.

Woodies and Hecht's also have opened their newest multi-million-dollar merchandising machines out in Fairfax County, setting the pattern for half a decade of development and giving the chief executives an opportunity to expound on their goals.

Woodies will continue to remodel its Washington stores and move aggressively into the Baltimore market, says Hoffman, chairman of the company which is already on everbody's list of the most successful independent department store chain in the country.

Hecht's is shaking its once-somewhat-stodgy image and aiming to improve its sales to upper-income consumers. "The development of our 'better' business is a major strategy," stresses Hecht president Zazulia. "It's a chain-wide strategy, a May Company strategy, and a Hecht Company strategy for the Washington-Baltimore area."

A veteran merchandizing man, who's worked his way up from assistant buyer to boss, Zazulia revels in the brass and bronze tones of Hecht's newest store. He's not embarrassed when people tell him the place doesn't look like a Hecht's store; he says the others will be looking like this, not so long from now.

Zazulia won't make public promises about the downtown Hecht's store, but he says the company is negotiating actively with developers of the complex to be built atop the Metro Center subway station and is "exploring alternatives" for giving downtown consumers the kind of shopping provided to Fair Oaks suburbanites.

Four other Hecht's stores are getting their own version of the new men's and women's active sportswear department called Bay Outfitters introduced at Hecht's in Fair Oaks, and all the stores are getting some of the same merchandise. If the name happens to sound like Hudson's Bay Outfitters and the clothes look like Britches' Great Outdoors, it's no accident.

When Zazulia toured the store on opening day, he talked about building "mini-theatres" to create "pockets of excitement," about tracing merchandizing themes from the designer boutiques to the budget department. That's not the language of a languishing chain store.

Zazulia responds to Woodies' strength as a locally owned and operated retailer by pointing out exclusive merchaindise from a hot new sportswear maker, discovered by the California division of the May Department Stores, Hecht's parent.

Across the sprawling but sparsely settled Fair Oaks mall from Hecht's Woodward and Lothrop Chairman Hoffman describes that company's newest store as "sensational, the best we've ever built."

The newest Woodward and Lothrop store represents $5 million worth of concrete and steel, another $3 million or $3.5 million of display cases and fixtures, $5 million of merchandise and a good dose of Hoffman.

Walking through Fair Oaks a couple of days before the store opened, Hoffman notes that the custom-made display stands in the ladies' shoe department are too high. By opening day, they are cut down.

The Woodies chairman acknowledges his stores close to maximizing their penetration of the Washington market but says pushing into Baltimore will keep the company growing. Noting that already a Baltimore magazine has decided the best department store service is to be found at the Woodward & Lothrop store at Columbia, Hoffman says the Maryland market is ripe for Woodies expansion.

Baltimore is also on the 1980s itinery of Garfinckels's Detwiler. "We visualize that our name is exportable," he says, citing the success of a nationwide mail-order operation that has been growing with little notice in the Washington area.

Construction of a new distribution center in Prince Georges county will space in the downtown Garfinckel's for retail use, and Detwiler charts an expansion campaign that starts in Annapolis this month, then goes to Columbia, then likely to a new Rouse Company mall called Painters Mill in Baltimore County.

Although a speciality store like Garfinckel's does not have to build as many stores in a city as a department store like Woodward & Lothrop to capture a competitive share of the market, Detwiler says that, "If I go to Baltimore, I'd be committed to at least one other store."

Garfinckel's is negotiating with Rouse about both Painters Mill and Columbia and could open in Columbia Mall as early as 1982.

Although men's wear is a growth target for Garfinckel's, there was not enough room in the Fair Oaks store for a men's department, and there will be no men's clothing in the small 16,000-square-foot store that will open next fall at the Georgetown Park complex.

And where else is Garfinckel's headed? "If there are two areas in which I feel we are underrepresented, it is Tysons Corner and Chevy Chase," adds Detwiler. And there's always southern Virginia and North Carolina, two market areas where other stores of the Garfinckel, Brooks Brothers, Miller and Rhoads operation are strong.