Lawrence and Dottie Storer of Gaithersburg are willing to swap the services of a plumbing contractor for a down payment on a house they're trying to sell.

The owner of a Washington restaurant recently redecorated his dining room by indirectly bartering meals for new furniture and fittings.

Virtually every radio station in Washington is willing to trade commercials for other services, and Robert Nunn and Clyde Fabretti are looking for anyone who wants to swap something for 15,000 pounds of bat guano.

Barter is booming in the Underground Economy. From the "successful swaps" column of the magazine Mother Earth News to the fine print of Internal Revenue Service regulations, the word is out: Barter is back.

Two Washington-area barter brokers say they are arranging to trade goods and services worth several millions of dollars a year for more than 2,000 local businesses.

Six nationwide, franchised bartering chains with more than 200 members and lots of independents will trade nearly $350 million worth of goods and services, estimates the International Association of Trade Exchanges, the industry's lobbying arm.

The barter brokers say their trading is done mostly by companies that are a little short of cash but have excess inventories to swap.

They also insist they are not part of the subterranean economy. "We're about as underground as Dart Drug," says Fabretti, partner in a local barter exchange and vice president of the industry association.

But students of the underground economy always include barter in estimates of off-the-books business because virtually none of this trading shows up in official economic statistics.

Most barter also escapes taxation, the Internal Revenue Service claims.

Generally, the value of any swapped goods or services is supposed to be counted as taxable income to both parties, just as though they had been paid. But is very difficult for the IRS to keep track of trading that is usually done informally and without records of any kind.

The IRS has launched a "Barter Project" to crack down on unreported income from trading. So far the IRS hasn't found much money, but it has won a series of court decisions giving it access to the records of barter organizations.

Like much in the underground economy, barter, in and of itself, is not illegal. Some methods of trading your way out of taxes are written into the federal tax code, and others have been developed by creative traders.

The owners of the Galliher & Bro. lumberyard on the Georgetown waterfront recently swapped land for a suburban site and a downtown office building. They were able to cash in years of appreciation without paying any capital gains taxes because the law permits tax-free exchanges of real estate.

In broadcasting, travel and entertainment, barter is a standard way of doing business -- the commercial time that isn't used, the airplane or theater seat that sits empty are worthless tomorrow.

Many doctors and dentists exchange services with professional colleagues, providing medical care to each other's families for free or at much below regular rates. One Washington dentist with several artists for patients has a gallery of paintings and prints that attest to his skills as both a dentist and a barterer.

As part of airline deregulation, the Civil Aeronautics Board recently opened barter to airlines, allowing them to trade tickets on undersold flights for goods and services they need.

Federal tax collectors say some traders simply are not counting barter earnings as income and that others are valuing their trading gains at far less than they are worth.

The question is how to evaluate and tax barter business is likely to end up before either Congress or the federal courts.

The barter advocates claim tax evasion is not their goal and predict that trading will continue to grow rapidly regardless of what the government does about it.

"Once you get into trading, you really get hooked," said Fabretti who, with partner Nunn, operates one of two Washington barter services, National Commerce Exchange. The Springfield-based NCE has 17 franchised branches in operation and several more signed up, he added.

Fabretti says his firm has arranged for a subsidiary of Midas Mufflers to swap a batch of vans, has enabled several business owners to trade for swimming pools and currently is looking for someone in the market for fertilizer who could take their inventory of bat manure off their hands.

In Silver Spring, Perry Constantinides and his wife Gloria run the five-year-old local franchise of Barter Systems Inc. of Nashville, another of the national chains.

Both firms work in the same way, serving as bookkeeper, clearinghouse and referral service for businesses they want to barter.

Initial membership in barter groups costs from $150 to $350 a year, with lower fees for renewals. The barter broker collects a 10 percent commission on each trade, in the merchandise that's traded.

Some barter companies make their money by matching two traders who are looking to acquire each other's products. Others trade for their own account, taking in widgets on one deal, then swapping the widgets for whatchamacallits when a widget fancier comes along. Atwood-Richards Co. of New York is the oldest and biggest of that type, a $100-million-a-year business that specializes in multiple trades.

But the organized trade exchanges use a different technique, a method that amounts to printing their own private money, called "trade dollars" or "barter credits."

Take the case of the Storers of Gaithersburg, who operate their own real estate and property management business and own a string of rental houses in the Maryland suburbs.

They're trying to sell a couple of their houses and, in an unusually creative financing deal, are willing to barter for the down payment through Constantinides' Barter System franchise. What they really need, Dottie Storer explained, is the services of a good heating and air conditioning contractor to handle repairs on their rental units.

Instead of finding a heating contractor who wants to buy a rental house -- a potentially problematical match -- Constantinides is trying to find another of his 1,000 members to buy the house. CAPTION: Illustration, Dutch West India Co. Governor Peter Minuit obtains Manhattan from Indians in 1626 for $24 worth of beads, cloth and trinkets. Engraving Courtesy Martin Luther King Library