Bed-and-breakfast rooms are becoming increasingly popular as charming alternatives to roadside motels and high-rise hotels. In fact, in recent years more than 170 "B & B" reservation services have emerged across the country, at least a dozen of them in Washington, Maryland and Virginia.

Each service represents a variety of bed-and-breakfast lodgings, providing travelers with a wide choice of places with only one phone call.

The local services list several hundred B & B lodgings that range from city apartments, townhouses and homes to working farms and country estates, some with pools and tennis courts. The lodgings can be found throughout the Washington area -- from Maryland's Eastern Shore to the Pennsylvania Dutch Country to Virginia's Shenandoah Valley. You can even rent an anchored yacht for the night either on the Annapolis waterfront or in Baltimore's Inner Harbor.

Bed-and-breakfast places generally are private residences that take in paying guests on a part-time basis, and usually they have rooms for no more than one or two individuals or couples at a time. (B & Bs should not be confused with city or country inns, which are in the tourist business full time and tend to have many more rooms available.)

While local B & Bs get visitors from all over the country, much of their business, managers say, comes from area residents. Travelers are seeking them out for quiet weekend getaways or as part of sightseeing vacations to the region's many historic sites.

And business travelers, too, have discovered B & Bs. They like the friendly home-away-from-home environment as a change of pace from convention-crowded hotels and motels.

The attractions of B & B lodgings are their individuality (some are elegant historic homes) and the customarily personal welcome guests receive. The hosts can be especially helpful with sightseeing and dining tips.

"This mode of lodging is your cup of tea if you are willing to trade bell hops and room service for the true luxury of being a guest in the home of a hospitable local host," advertises Bed and Breakfast of Tidewater Virginia in Norfolk.

Another attraction is that B & B inns often are cheaper than other accommodations, particularly in cities, although this is not always true. B & B hosts generally are not interested in guests who choose their homes simply because they want the least expensive accommodations.

In Europe, where bed-and-breakfast inns are a longstanding tradition, they usually are among the lowest-priced places to stay. But in the United States -- or at least in the Washington region -- many of the host homes are quite substantial residences. They cater mostly to professionals and other higher-income travelers who are looking more for charm (and a more insightful look at the region they are visiting) than budget-priced rooms.

"People from England say we should change the name," says Lyn Benson of Bensonhouse, a Richmond reservation service, because bed-and-breakfast homes in the United States are "much grander" than those in Europe. In a few cases, they compare favorably to large estate homes in the British countryside.

Nancy Stewart of Shenandoah Valley Bed and Breakfast Reservations says the homes on her list "must be exceptional in some way." She represents 13, among them historic homes, restored farms and at least one very modern house that uses solar energy.

Prices throughout the area range from about $35 a night double (often with shared bath) up to $90 a night for deluxe rooms in the grander homes. The price includes either a continental or full breakfast, depending on the practice of individual hosts. Harbor yachts, incidentally, are at the higher end of the price range.

Because B & Bs are mostly part-time operations, reservation services have emerged to assist both host homes and guests complete the reservation arrangements as conveniently as possible. Each service represents anywhere from just a few to 200 or more individual B & Bs. (Some B & Bs, however, operate independently of reservation services. State or community tourist offices can direct you to them.)

Hosts find the services helpful in freeing them from advertising or answering the phone day and night. The reservation services perform both tasks.

For guests, the B & B services provide one-stop shopping. You call or write to one in an area you want to visit. The service can tell you what is available or mail out a descriptive list of the homes it represents.

Sally Reger of Guesthouses, a Charlottesville reservation service, says she can direct guests to the most conveniently located homes, as well as match host and guests according to a variety of criteria: nonsmoker, dog fancier, vegetarian or who has the most comfortable bed.

Most reservation services say they regularly inspect the homes to make sure they maintain proper standards.

B & B rooms, of course, are not for everyone. Many do not take families because they don't have enough space. As a guest, you may be expected to arrive at your destination during a certain specified time period, so the host won't have to spend the day at home waiting to let you in. The room may not have either a TV set or telephone.

Most B & B services prefer at least a week's advance notice (or even longer), although a few will accept same-night reservations. And many reservation services set limited times when they are available to take reservations calls. Sometimes, it may take repeated attempts to reach them by phone.

Nevertheless, reservation services say bed-and-breakfast business is increasing as more travelers become aware of them.

Eleanor K. Chastain of Sweet Dreams & Toast, which represents about 100 hosts in the Greater Washington area, says her business has doubled in the past year. During the spring, her homes often are fully booked, and some guests make reservations months in advance.

The Travel Tree, a small reservation service in Williamsburg with about a dozen host homes, "tends to fill up April through October," says manager Joann Proper, and again at Thanksgiving and Christmas when this major tourist community decorates for the holidays.

Who is staying in B & Bs?

Richmond's Lyn Benson says her clientele tends to be more sophisticated travelers who have been exposed to bed-and-breakfast accommodations in Europe. Or they are architectural or history buffs who are "looking for something different" in a place to stay. She has particularly noticed many bankers, lawyers and museum curators.

Among the reservation services in the Washington area: MARYLAND:

Amanda's Bed and Breakfast: About 90 homes in Baltimore, the Baltimore suburbs, Maryland's Eastern Shore and York, Pa. Offerings include apartments with a view of Baltimore's Inner Harbor and yachts anchored in the harbor; doubles range from $35 to $65, yachts $85 to $100 a night. Operating hours: Daily, 24 hours. Box 42, Long Green, Md. 21092, (301) 665-1333 or (301) 321-5471. The Traveller in Maryland: About 200 private homes throughout Maryland and anchored yachts in the Annapolis area; $45 to $65 a night for two, yachts beginning at $75 a night. Hours: Monday-Thursday, 9 a.m. to 5 p.m.; Friday, 9 a.m. to noon. 33 West St., Annapolis, Md. 21401, 261-2233 (no charge from D.C. area) and (301) 269-6232. VIRGINIA:

Bed and Breakfast of Tidewater Virginia: About 35 houses in the Norfolk area, including Norfolk, Virginia Beach, Portsmouth, Chesapeake, Virginia's Eastern Shore and the Northern Neck; $30 to $75 a night. Hours: normal business. Box 3343, Norfolk, Va. 23514, (804) 627-1983. Bensonhouse of Richmond: About 40 rooms or apartments in Richmond and its suburbs; singles $28 to $72 and doubles $36 to $84 a night. Hours: Monday-Friday, 10 a.m. to 5 p.m.; answering service other hours. P.O. Box 15131, Richmond, Va. 23227 (include stamped, self-addressed envelope), (804) 648-7560 or (804) 321-6277. Blue Ridge Bed and Breakfast: About 40 farms, homes and inns (some with swimming pool) in the northern Shenandoah Valley, including the communities of Waterford, Winchester, Paris and Luray; mostly $35 to $45 a night. Rocks & Rills, Rte. 2, Box 259, Berryville, Va. 22611, (703) 955-1246. Guesthouses: About 40 homes (including country estates) in the Charlottesville area, and also Luray and Staunton; $40 to $72. Hours: Monday-Friday, noon to 5 p.m. P.O. Box 5737, Charlottesville, Va. 22905, (804) 979-7264. Princely Bed and Breakfast: Thirty-one homes in Alexandria, about half of them built in the 18th century; about $65 a night (all with private bath). Hours: Monday-Friday, 10 a.m. to 6 p.m. 819 Prince St., Alexandria, Va. 22314, (703) 683-2159. Rockbridge Reservations: About 15 private homes in Lexington and Rockbridge County (including some country homes with pool or tennis court, others with nearby hiking and stream fishing); about $45 a night for two. Hours: Monday-Friday, 10 a.m. to 4 p.m. Sleepy Hollow, Brownsburg, Va. 24415, (703) 348-5698. Shenandoah Valley Bed and Breakfast Reservations: Thirteen homes and farms (from restored-historic to modern-solar, including two featured on local house and garden tours) from Winchester to Staunton in the Shenandoah Valley; $35 to $75 a night. Hours: daily, 4 to 11 p.m. P.O. Box 305, Broadway, Va. 22815, (703) 896-9702 or (703) 896-2579. Sojourners Bed and Breakfast: Very small service (four homes) in the Lynchburg area; singles $32 to $46 and doubles $36 to $50. Hours: daily, before 10 a.m. and after 6 p.m. 3609 Tanglewood Lane, Lynchburg, Va. 24503, (804) 384-1655. The Travel Tree: About a dozen homes or private guest cottages within one to five miles of the historic district of Williamsburg; doubles from $35 (a room with private bath) to $75 (a private guest cottage) a night. Hours: daily, 5 to 9 p.m. Three-day advance registration required. P.O. Box 838, Williamsburg, Va. 23187, (804) 253-1571. WASHINGTON:

Bed and Breakfast League: About 45 homes in Washington and the suburbs (including a Georgetown house for somebody who likes cats); singles $40 to $50 and doubles $50 to $68. Hours: Monday-Friday, 9 a.m. to 5 p.m. 3639 Van Ness St. NW, Washington, D.C. 20008, (202) 363-7767. Bed 'n' Breakfast Ltd. of Washington, D.C.: About 70 homes and apartments throughout Washington; singles $30 to $65 and doubles $40 to $75 a night. Hours: Monday-Friday, 10 a.m. to 5 p.m. P.O. Box 12011, Washington, D.C. 20005, (202) 328-3510. Sweet Dreams & Toast Inc.: About 100 private homes in the Greater Washington area, but mostly in the District of Columbia; singles $35 to $55 and doubles $45 to $65. Hours: Monday-Friday, 11 a.m. to 5 p.m. P.O. Box 4835-0035, Washington, D.C. 20008, (202) 483-9191. WEST VIRGINIA:

West Virginia's state tourism office maintains a list of about 15 individual bed-and-breakfast homes and inns. For details: West Virginia Travel Division, Department of Commerce, State Capitol, Charleston, W. Va. 25305, (800) 624-9110.

DELAWARE: Bed and Breakfast of Delaware: About 24 homes in northern Delaware and adjacent Pennsylvania, primarily the Brandywine Valley area (Longwood Gardens, Winterthur Museum and Garden); doubles $35 to $60. Hours: daily, 8 a.m. to noon and evenings. 1804 Breen Lane, Wilmington, Del. 19810, (302) 475-0340. PENNSYLVANIA:

Bed and Breakfast Association of the Delaware River Valley: This is not a reservation service, but you can write or phone (business hours) for information about B & Bs in Bucks County, Pa., the historic countryside just north of Philadelphia. Bucks County Tourist Commission, 152 Swamp Rd., Doylestown, Pa. 18901, (215) 345-4552. Bed and Breakfast of Philadelphia: About 100 homes in Philadelphia, the suburbs, the Valley Forge area and Bucks County; doubles $45 to $60 a night. Hours: Monday-Friday, 9 a.m. to 5 p.m. Directory, $5. P.O. Box 680, Devon, Pa. 19333-0680, (215) 688-1633. Bed and Breakfast of Chester County: About 40 homes in Chester County, Pa. and northern Delaware; doubles $35 to $85 (a room with a private fireplace on a country estate). Hours: daily, 8 a.m. to 6 p.m. P.O. Box 825, Kennett Square, Pa. 19348, (215) 444-1367. Bed and Breakfast of Lancaster County: About 25 homes and farms in Pennsylvania Dutch Country and Harrisburg, Hershey, York and Gettysburg areas; doubles $30 to $90 a night. Hours: Monday-Friday, 8 to 9:30 a.m. and after 5:30 p.m. and anytime weekends. P.O. Box 215, Elm, Pa. 17521, (717) 627-1890. NEW JERSEY:

Bed and Breakfast of New Jersey: About 200 homes, apartments and villas throughout the state, including the Jersey Shore and Atlantic City; doubles from $30 up to $200 a night for an Atlantic City villa. Hours: daily, 9 a.m. to 9 p.m. Suite 132, 103 Godwin Ave., Midland Park, N.J. 07432, (201) 444-7409. Town and Country Bed and Breakfast: About 12 private homes and six inns in the Delaware River Valley, including Bucks County, Pa. and Hunterdon County, N.J.; doubles $30 to $130 (at an inn). Hours: Monday-Thursday, 7 to 9 p.m. P.O. Box 301, Lambertville, N.J. 08530, (609) 397-8399.

A current list of about 170 reservation service organizations in the United States is published by Sweet Dreams & Toast. The 1985-86 edition, just issued, costs $3. To obtain a copy, write: Sweet Dreams & Toast Inc., P.O. Box 4835-0035, Washington, D.C. 20008. Enclose a long self-addressed and stamped envelope.