LESS THAN A MONTH after losing in the District of Columbia Democratic mayoral primary, Sterling Tucker was reported be in line for a high-ranking job in the U.S. Department of Housing and Urban Development -- assistant secretary for fair housing and equal opportunity. Because HUD Secretary Patricia Roberts Harris has been a friend and sometime political associate of Mr. Tucker, the arrangement could easily be interpreted as nothing more than cronyism. Then came reports of the failure of the Tucker for Mayor campaign to file a financial report on time, which raised some additional uneasiness about the appointment. Now President Carter has made the nomination official -- and we think it is a good one.

To begin with, Tucker campaign officials report that debts have been settled and fines paid. As for the job at HUD, it can and should be an important one. It involves the sensitive enforecement of federal fairhousing and affirmative-action requirements throughout the nation. This means, for example, monitoring of state and local governments' hiring of minorities to work on HUD projects, checking on discriminatory zoning and land-use policies and overseeing the distribution of "fair share" housing-program funds for projects in metropolitan regions.

These are fields to which Mr. Tucker does bring valuable local and national experience. His many years as the Urban Leaguehs director of field services, his role in assisting in early fair-housing and urbanrenewal projects in this city and his work as a board member of such organizations as the National League of Cities and the National Association of Regional Councils and other organizations should stand him in good stead at HUD.

Though we did not support Mr. Tucker for mayor last September, we noted then that he had served the District of Columbia well as chairman of the council -- a thoughtful techniciar who was familiar with the nuts and bolts of the machinery of city government. How logical, therefore, that Secretary Harris would turn to Sterling Tucker to fill an important vacancy.