WHETHER THE QUESTION is rent control, adequate housing for lower-income residents or the skyrocketing costs of homes, the city's housing policies affect all District residents - no matter where they live or what their income. So what are the housing policies of the Democratic candidates for mayor - Marion Barry, Sterling Tucker and Walter Washington? The three are of one mind in many respects, including their support - misguided, in our view - of rent control. Though each has said that the current rent-control program isn't working well, none has acknowledged the fact that local rent controls will not erase the effects of national inflation. On the contrary, unrealistic ceilings on rents serve only to drive landlords out of the city's housing market - reducing the supply of housing and creating greater financial pressures for what's left.

But there are some sharp divisions between the mayor, on the one hand, and Mr. Tucker and Mr. Barry on the other. The mayor, for example, suggests that the existence of a local housing problem is simply a matter of perception. He points to several thousand apartments that have been built as proof of his successful efforts to provide housing for lower-income households. Moreover, Mr. Washington claims that, as a result of his efforts, an increasing number of middle-income households are moving into the city - buying homes, paying taxes and helping the District to grow. The way the mayor sees it, all the other housing problems will work themselves out, given more time and more money from the federal government.

True, there has been an increase in the number of apartments built in urban-renewal areas over the past few years - though, in large measure, they only replace the units that were destroyed during the 1968 riots. In challenging the mayor's housing record, Mr. Barry and Mr. Tucker cite his inattention to such matters as fixing up the thousands of abandoned units scattered around town (at least 2,000 of which are owned by the city government), mismanagement of federal money for lower-income housing programs (which, according to federal officials, includes pading budgets with unnecessary administrative costs while not even spending available money to assist lower-income households) and persistant unwillingness to prepare an overall housing plan for the city.

Mr. Tucker and Mr. Barry are correct in their assessment that the mayor's housing record is wanting. But they do not agree on all points. For one thing, Mr. Barry has done a better job, in our view, of coupling housing needs in neighorhoods with an overall plan for city growth. And although Mr. Tucker says that it might take as long as two years to come up with a housing policy for the city, Mr. Barry's intention is to produce one in fairly short order - using the work already done by numerous community groups as a basis for such a plan. Moreover, Mr. Barry has a long record of taking the mayor to task over the management of the Department of Housing and Community Development. Two years ago, for example, when the mayor announced that he had selected Lorenzo Jacobs as head of that agency - after taking almost two years even to come up with a name - Mr. Barry wrote to the mayor opposing the appointment. All of the members of the D.C. Council - except Sterling Tucker - joined in Mr. Barry's protest; now even Mr. Tucker agrees that Lorenzo Jacobs should be replaced.

The election of a new mayor would not eliminate the city's housing shortage or automatically ease the financial strain on low-income households. But at least the campaign has brought to light - and more sharply into focus - some refreshing alternatives to the disappointing results of the housing programs of the past 10 years.