ST.ELIZABETHS is a federally operated mental hospital in the District. Or at least it has always been supposed to be federally operated. Until recently, however, accounted for its long slide into disrepair and disarray. But now, we are pleased to report, it has found a friend in the federal government: The Department of Health, Education and Welfare, under the direction of Secretary Joseph A. Califano Jr., has decided to own up to its statutory responsibility to the hospital, and things are looking up. The first evidence of this is to be found in the newly named director, Dr. Charles Meredith, who brings to the job not only the good opinion of his colleagues, but also some sound ideas about how to improve the treatment of patients. One way he would do this is to stop the present practice of confining patients there who are ready to be released but have no place to go. Already an effort is under way to identify those patients.

The next step will be to find some place other than overcrowded St. Elizabeths to house them. Some preliminary discussion has begun about how the city and HEW can coordinate transferring these patients into community facilities. And, in an attempt to sort out its management confusion, HEW - with the help of outside consultants - is studying ways in which the hospital can be run more efficiently.

These steps are a good beginning, but the problems of St. E's have taken decades to accumulate and will undoubtedly take years of continuing attention to correct. A recent presidential statement on the District fixes a target date of 1982 for getting the hospital up to standard and fully accredited. At that time, the hospital is to be turned over to the city government. As the city and HEW work toward that date, they should be thinking hard about how St. Elizabeths can be transferred to the District's control without putting an unbearable strain on local finances. There is much to be said for having the hospital run by the District government, but the city is not going to be able to shoulder this added financial burden without some help. Unless the problem is faced squarely and dealt with realistically, the city will have a hospital that it can't pay for, and the deterioration will start all over again. The time to begin working out is undergoing a general overhaul that will determine the scope of its operations and, theefore, the extent of its financial needs.