IT HAS ALREADY happened several times this year: an ambulance arrives, sirens screaming, at the C Street offices of the District's Department of Human Resources. The back door of the ambulance opens. Inside are old people. The ambulance driver unloads them. A hospital worker tells DHR officials that his private hospital has no room for these elderly people, who are not in need of hospitalization, but rather of group home or nursing home care. The ambulance drives off, and the old people are left as orphans on the city's doorstep. Since the city has no space in its nursing homes or group houses -- it is an old and awful story -- the old people are sent to D.C. General. As the city's only public hospital, it has to take them.

D.C. General is now overloaded with the old. And in the past year the shortage of proper facilities has reached crisis proportions. After April's fire in a Lamont Street group house for the elderly, the city began licensing community residential homes. Several that were in operation were closed because the owners did not want to spend the money to bring their places up to city standards. So far, only six of the homes have been licensed by the city; and the elderly are finding increasingly stiff competition for places in group houses that do exist, since laws have been passed urging "deinstitutionalization" of addicts, the mentally disturbed and the handicapped.

D.C. Village and Glendale Hospital, the District's facilities for long-term care of the elderly, have waiting lists in the hundreds and are already overcrowded. Social workers report that there are now thousands of old men and women in the city left to live in cheap, filthy rooming houses because neither they nor the city can find a better place for them. And a report by the National Capital Medical Foundation released last Monday shows that the number of elderly in need of nursing home care in the city grew by 35 percent last year. The report added that the city and federal government wasted $1.2 million last year paying hospital fees for elderly persons who belonged in nursing homes but stayed in hospitals because they had nowhere else to go.

What can be done? The city plans to expand its capacity at D.C. Village and has approved plans by developers to build homes that will add 1,200 rooms for the elderly. But DHR Director Albert Russo says the actual homes are years from being built. He wants more help from private developers in immediately opening places for these people to live. Mr. Russo claims that although the city has been reimbursing the foster-care homes for the elderly in full for all poor persons since 1977, that has not encouraged the private developers to invest in more such houses for the old. The developers reply that there is not a large enough profit margin in nursing homes or group houses. In addition, they say, insurance is hard to come by, and there are other special insurance problems.

To relieve the shortage, the city needs to give the developers a helping hand. Zoning laws that specify where the homes can be located must be relaxed so developers will have a wider area of the city in which to put the homes. City residents will have to be persuaded to accept these homes in their neighborhoods, which means there has to be a campaign of explanation and education. The amount of insurance a group house or nursing home needs should be set by the city right away: as it stands, a developer has no idea what his insurance costs will be if he opens a nusring home here. The city should also work with insurance companies in setting the liability rates so that insurance firms will want to insure the homes. And, finally, the city may need to offer the developers some of its boarded-up properties at low prices and special low tax rates for use as group homes and nursing homes. In that way, developers will see a minimum of difficulty and a maximum of profit in bringing a nursing home or group house for the elderly to the city.