Rachel Riley always takes her kids along to the office.

In fact her employer, Mount VerR non Hospital, encourages her to bring the two preschoolers.

Mount Vernon is one of a small but growing number of Northern Virginia employers to become involved in the business of day-care.

"The program is a lifesaver," said Riley, a medical secretary at Mount Vernon, which opened a day-care center for employes' children early this month. "I recently had another job offer, but I elected to stay at Mount Vernon because of this center."

"The interest in the business community is just starting," said Jane Angrist, Alexandria's child-care coordinator, who is working with the Chamber of Commerce to stir up local interest in the corporate day-care concept. "It's still a coming thing."

In recent years, a small number of concerns around the country--notably the Amalgamated Clothing and Textile Worker's Union in Verona, Va., and Boston's Stride Rite Corp.--have begun offering employes some form of subsidized day-care, either at the place of business or nearby. Other firms have started clearinghouses for local child-care information to help their workers find quality, reliable child-care.

Although it's still a trickle and not a trend, some Northern Virginia businesses also have begun to gather facts and figures about the increasing demand for day-care among their workers as the number of families with both parents working increases each year.

"We have been working toward helping raise the consciousness of employers about various ways to provide assistance to their employes for day-care," said Judith Rosen, director of the Fairfax County Office for Children. The office, she said, has fielded about 15 recent requests from Fairfax businesses wanting child-care information.

One of these was the National Wildlife Federation in Vienna, a nonprofit organization with close to 500 employes.

"We are one step away from starting our own day-care facility," said Nan Clarkin, a member of the company's day-care committee. An employe survey on the idea yielded response that Clarkin termed "very favorable, even from employes with no children." The company has started gathering information and applying for grants to help start the program, she said.

The federation envisions a double benefit from getting into child-care: "We can take care of employes' children, plus we would have a lab setting to develop curriculum that schools can use with science and environment and conservation emphasis," said Clarkin.

Three Northern Virginia hospitals--Mount Vernon, Arlington and Jefferson--offer on-site day-care. Hospitals have been in the forefront of the corporate day-care movement here and throughout the country partly because of a nationwide nursing shortage and also because of their high percentage of female employes with irregular shifts, making child-care a problem.

According to a study released last May by the Fairfax County Child Care Advisory Council, 54 percent of all county children under age 12 live in a home where all adults are working, an increase of 46 percent since 1974.

Even with 193 licensed day-care centers and family day-care homes in Northern Virginia, the need for day-care is increasing. "We even have waiting lists filled with names of unborn children," said one center operator.

The Fairfax survey, which stressed above all the need to increase the supply of day-care in the county, specifically suggested that the county help employers plan, develop and operate day-care programs.

"There's a lot of interest now in corporate day-care," said Rosen. "So many more women with young children are working (now) so it's a recent need. It's become so much more expensive that families are looking for some sort of assistance in finding and paying for their day-care. Employers have assumed a whole variety of responsibilities--employe counseling programs, health care programs--and now some employes are looking for some sort of day-care assistance from their workplace."

"Remember the movie '9 to 5' ?" asked Betsy Shelsby, coordinator of family day-care at the Northern Virginia Community College Child Care Center. "One of the first things that Lilly Tomlin did after she tied up her boss and took over the company was to start a child-care center in the basement of the office building."

The Tomlin method may be the only solution at most businesses, which don't put day-care at the top of their priority list for employe benefits.

"We investigated setting up our own day-care facility after a few employes approached us," said a spokesman for one high-tech firm in Springfield who had called Rosen's office last year. "But we saw it would take $100,000 just to get the place set up. Another consideration was that we are located in an industrial park; and if I were a parent, I would prefer to have my kids in a residential neighborhood in day-care." The spokesman asked that the company name not be used lest "employes get their hopes up."

But despite its preliminary legwork, this company of about 350 employes was hit by government contract cutbacks. "The whole issue has taken a back seat now," added the spokesman. "Now we are just trying to keep people employed."

Rosen said the current economic climate need not rule out a company's involvement in day-care, however. "There are many options and it's just not on-site day-care or nothing," she said. "Many employes may not want to bring their child into work with them; they want the child near their home."

As options, companies could run a clearinghouse for outside day-care information for their workers or contract with an outside day-care center, which is what the Fairfax Hospital Association did.

Early this month it contracted with a nearby day-care center that would accept children of employes at Fairfax Hospital, Commonwealth Hospital and the association headquarters at special rates to be paid by parents. The hospital runs a shuttle bus service to take the children, ages 2 to 5, the mile between Fairfax Hospital and the day-care center.

Though the employer picks up only the cost of the bus in that arrangement, Mount Vernon Hospital spent $30,000 to begin its day-care center in a vacant wing. "The employes pay $55 a week, which is not cheap, but the center is staffed with a lot of very good people," said Mount Vernon Administrator Stephen Rupp. According to Frances Damico, the hospital's day-care director, 61 children have enrolled in the month-old center.

Rupp added that although the fees will cover day-to-day operations, the indirect costs such as use of the building and utilities will be provided as a subsidy by the hospital.

Businesses also could opt for the "cafeteria" approach to benefits, Rosen said. With so many two-parent working families, one parent's benefits often duplicate the other's. So, explained Rosen, a company could offer a full range of benefits--including vacation, sick leave, health care and day-care--and give employes the chance to choose the specific elements that would make up their own benefit packages.

Companies that have had the resources to start their own center have found the move good for employe morale and possibly even for productivity.

Sharon Davidson, director of the six-month-old day-care program at Arlington Hospital, said the 17-hour-a-day center has been a huge success and "has also helped in terms of people coming to work regularly and promptly."

Mount Vernon's Rupp said that although the center costs the hospital some money, the facility realizes other gains. "We feel it will keep us competitive in hiring skilled professionals," he said.

At Jefferson Hospital, this has already been the case. "In the last year, the hospital has been able to hire eight full-time and six part-time nurses because they offer these services," said Mary Jo Eagen, Jefferson's day-care director.

"I can save money on gas," said Mount Vernon's chief anesthetist, Carol Burgess, who brings her 2-year-old daughter to the center regularly. "And this facility is the best thing I've ever seen."

"The center gives me piece of mind," said Deborah Dannelly, a medical technologist at Mount Vernon. "I know that if something happens, I am right here."