PLYWOOD COVERS MOST OF the doorways and windows of the four large, vacant rowhouses in the 1300 block of S Street NW, and trash and foul odors fill the high-ceilinged rooms. The backyards are choked with weeds, discarded furniture, automobile parts and garbage. Years ago, these were elegant homes, with bay windows and fireplaces. Now they are empty, save for the nesting rats and the occasional vagrant. No landlord will be contacted to clean up or fix up the buildings - there is none to call. These house are owned by the District government. And they are only a small piece of a potentially large resource that the administration of Mayor Walter Washington has steadfastly refused to put to constructive use to help ease this city's cruel and continuing shortage of adequate housing.

By the District's own count, it owns almost 1,000 deteriorated homes and apartments that are vacant and uninhabitable; several hundred others are badly dilapidated, though somehow people continue to live in them. In some instances, these units have belonged to the city for eight or nine years, while officials have tried to figure out whether to renovate them, sell them or tear them down. Many of the abandoned units are scattered throughout the very neighborhoods where other government and community programs are beginning to show some results. In the 1300 block of S Street, for example - part of the Shaw urban-renewal area - residents at one end live in recently built, well-maintained public housing and those at the other end live in well-kept houses and apartment buildings. They are bitter about and discouraged by the filth of the city-owned buildings in the middle of their block.

These abandoned and decayed units bring vividly into focus the bankruptcy of the city government's housing policies. The cost of housing, whether for sale or for rent, is steadily increasing; the number of available homes and apartments, whether privately or governmentally owned, is dwindling. Low- and moderate-income households - people who live in the areas where most of this abandoned housing is located - are particularly hard hit. This city-owned housing could be sold cheaply to people of modest means who pledged to renovate the units and rent them at low cost or, for that matter, sold at a high price to speculators who would, most likely, resell them at higher prices. Officials could turn the units over to a private contractor who would agree to renovate them and rent them at low cost. Or the city itself could put the units back into use. It is incredible, not to say unconscionable, that the mayor and his housing aides seem to be incapable of summoning the energy or the imagination to do any of those things.

In recent days, three candidates for mayor have discussed the city's housing problems, with varying references to these abandoned units. Both City Council Chairman Sterling Tucker and Councilman Marion Barry pointed out the inadequacies of the city's present approach and alluded, at least, to the need to put city-owned housing to better use. Both emphasized an awareness of the urgency of the problem. In a low-key, almost off hand housing-policy statement of his own, Mayor Washington avoided altogether the subject of abandoned city-owned units as a means of dealing with the city's housing needs. In fact, for a fellow who made his reputation years ago as something of an authority on municipal housing problems, he had remarkably little new to offer by way of solutions to the District's housing problems. His program for the future, in other words, was entirely consistent with his past performance.

That's one thing about the mayor. He is consistent. And that's precisely why we are in favor of a certain inconsistency in the outcome of this fall's mayoral election. The incumbent city government's handling of the housing problem in general, and of the city-owned housing units in particular, is only one of the reasons we think it is time, as they say, for a change.