More than 10,000 new hotel rooms are planned or already under construction in the Washington suburbs, a hotel explosion that mirrors that occurring in the District.

Thirty-one new hotels or expansions of existing facilities are expected to produce an estimated 7,400 new rooms in the next three years in booming Fairfax County alone, which will double the existing hotel stock.

In Arlington County, economic development officials said that more than 4,600 new hotel rooms are planned for the next few years or are under construction, more than a 60 percent jump over the existing total of 7,481 rooms.

In Montgomery County, officials said, more than 1,100 new rooms are planned and 775 are under construction.

Officials in Prince William and Prince George's counties and the city of Alexandria also are expecting continuing booms in hotel construction.

Local economic development officials, consultants and commercial real-estate brokers are predicting that growth in the hotel industry in the Washington suburbs will increase as long as commercial growth continues, the economy remains stable and interest rates stay low.

"It's like a cavalry charge out here," explained Wayne Angle, the Homart Development Co. official in charge of building the 107-acre Tysons II development, which eventually will include two hotels.

"This place is going bananas with new hotels," said a Prince George's County spokesman.

Hotel consultants said the boom is a natural outgrowth of the commercial marketplace. According to consultant Ted Seale of Laventhol & Horwath, which tracks hotel development, "Companies locating in the suburbs have established the commercial bases needed to generate hotel rooms."

New hotels planned and those about ready to open are bringing a variety of accommodations to those who travel to the Washington suburbs. Some new facilities are tall and dramatic, catering to convention and conference needs. Many are smaller hotels aimed at attracting the more budget-conscious customer. Some hotels are in office parks as major centerpieces of mixed-use developments combining office, retail, residential and hotel spaces. All-suite hotels, such as Embassy Suites, are planned in almost every suburban jurisdiction.

Developers are experimenting in concept and design also. For example, the Ramada Renaissance Hotel, set to open officially March 22 on Rte. 28 near Washington-Dulles International Airport, actually is connected to an office building housing the much-publicized Virginia Center for Innovative Technology and other tenants.

Marriott Corp. and Ackerman & Co. have announced plans for a 280-room hotel at Ackerman's $500 million Washingtonian development along Interstate 270 near Shady Grove Road in Montgomery County. Hotel officials said the model to be built there was created especially for the suburban marketplace and will include smaller meeting facilities and fewer guest rooms than larger Marriott operations.

"Our suburban hotels are a gathering place for businesses," said June Farrell, a spokeswoman for Marriott Corp.

Older hotels and motels are being renovated to compete with new facilities. The Tysons Corner Marriott, built just five years ago, recently started major renovations, including changing its lobby and redecorating all guest rooms in the Chinese Chippendale style. The Tysons Holiday Inn also dramatically changed its interior and launched a major campaign to attract business clientele.

Both apparently were trying to fend off competition that is sure to come from new hotels nearing completion in the Tysons area. The 456-room McLean Hilton in the middle of the Westpark office development is under construction, and the 23-story Sheraton Hotel at Rte. 7 and the Dulles Airport Access Road, which includes conference rooms and substantial indoor and outdoor recreational facilities, is slated to open this year.

In Montgomery County, the old Linden Hill Hotel and Racket Club is being updated, according to county officials.

In addition to attracting weekday business travelers, suburban hotels are snagging their share of the tourists who come to Washington for weekend trips, consultant Seale explained. That is because most of the hotels are located along major arteries or are easily accessible to Metro subway lines.

While some developers foresee short-term gluts in such areas as Tysons Corner and Shady Grove, industry sources predicted that any oversupply would be absorbed over the next five years if economic conditions remain strong.

"The industry historically is an up-and-down industry. It has been up for 10 years," said Joe Ramsey, executive vice president of the Virginia Hotel and Motel Association in Richmond. He said developers and investors building in the Washington suburbs have a solid base of government, government-related industries and trade associations to help guarantee strong hotel traffic.

Seale said the hotel industry could be hurt by the long-range implications of budget cuts mandated by the Gramm-Rudman-Hollings law.

"Does that bill mean that more lobbying will be necessary or does it mean that less will need to be done? Does it mean that it will be less important for businesses and trade associations to have a Washington location?" Seale asked.

He said he thinks it will be even more important for lobbyists to be in Washington. That would help ensure the financial stability of many hotels now being built or planned.

There currently are plans for 31 new hotels or expansions in Fairfax, according to a new report by the Fairfax County Economic Develop-"Companies locating in the suburbs have established the commercial bases needed to generate hotel rooms." -- Ted Seale of Laventhol & Horwath ment Authority. Those projects will add more than 7,000 rooms to the existing rooms that are now contained in about 35 hotels, EDA officials said.

Prince George's officials said they expect five new hotels to be finished this year, adding 745 rooms to the existing 2,550 rooms now available.

According to Joseph Edwards, a spokesman for the Prince George's County economic development office, proposed expansions would add another 600 rooms. Twelve new hotels, whose size has not yet been determined, are being proposed throughout the county, especially in the high-tech areas near Bowie, in the Laurel area and close to the 50-story Port America World Trade Center project planned along the Potomac River south of the Woodrow Wilson Bridge.

According to Bernadette Plunkett, tourism director for Prince William County, site plans have been filed for 507 new hotel rooms to be added to the present base of 1,242 rooms.

In Montgomery County, there are 1,105 rooms in the planning stages and 775 under construction. There now are 5,196 rooms in Montgomery, according to county statistics. Popular areas for new hotels in Montgomery are near Gaithersburg, Germantown, the I-270 corridor, the Shady Grove Metro area and the Research Village area.

Richard Flaherty, of Alexandria's Chamber of Commerce, said his city attracts more tourists to conferences than all areas of Virginia except for Virginia Beach and Norfolk. He said "several hundred" new rooms are being planned in Alexandria; 2,540 hotel-motel rooms exist now. New to Alexandria during the past year were the $56 million Radisson Mark Plaza, a 30-story, 428-room tower whose grounds include an 80-acre nature park, and an unusual European-style inn, known as Morrison House.

In Arlington, where the Metro subway has encouraged massive commercial development, hotel forecasts are bright, according to county officials, who say Arlington's proximity to the District is hard to match. Site plans for 3,817 new hotel rooms recently were approved in Arlington, and 842 rooms are under construction. Arlington now has 7,481 hotel rooms, according to Francine Bradshaw of the county's economic development group.

In Loudoun County, officials said there now are nearly 800 rooms, more than double the number a year ago.