The city government failed to deal with the issue of preventive maintenance in the District's public housing projects even as the projects steadily went downhill, with the result that needed repairs have now stacked up to the point that the city has launched a "Maintenance Backlog Reduction Program."

That was just one of the many messages tucked away in Mayor Marion Barry's 73-page report on the condition of public housing released this week. Acknowledging that all is not well, Barry stressed that he wants the entire city to know that public housing is a priority for his administration.

Barry hopes the report will counteract media reports about poorly maintained units and the housing department's failure to adopt the corrective steps that the U.S. Department of Housing and Urban Development recommended in a 1984 audit.

The general thrust of the city's defense is that the major problems were inherited and that despite a decade of efforts, a lack of needed funds has caused delays in correcting the problems. Barry says the city government has had to deal with the "past errors of the federal government, stretching back to pre-World War II days."

However, while it is true that the federal government managed public housing until the city took over in 1975, some tenants' complaints -- leaks that have gone unrepaired for months, falling ceilings, the absence of heat in the winter and rat- and roach-infested units -- date to no earlier than the first years of the Barry administration.

Barry maintains that by the time his administration came to power, the housing authority had a $10 million deficit and the vacancy rate was 13 percent. He also says that when he discovered that the city had a $300 million accumulated deficit, the housing department was forced to make do with a staff that was "too low to combat effectively the growing problems of property deterioration and maintenance backlogs."

During that time, there was no preventive maintenance plan, which even the city officials say is needed to "spot instances of disrepair before they escalate into major maintenance problems." Barry's report, however, concludes that it would have been some "sort of bureaucratic joke" to focus on preventive maintenance while the daily requests for repairs grew.

For the future, the administration promises that the situation will get better, partly due to anticipated changes in procedures and staff size.

A new maintenance reporting system is being developed to coordinate maintenance activities, a program for reducing the maintenance backlog will be implemented, and a "Special Strike Force" will be formed to respond "promptly" to tenant maintenance requests.

Barry also promises that the public housing staff will grow from 786 workers today to 960 sometime next year. He promises that the staff responsible for monitoring the multimillion-dollar public housing renovation program, only 14 strong in 1981, will increase to 86 next year.

Yet housing department officials acknowledge that they are still having trouble filling vacant positions for skilled workers and public housing managers. Even after a nationwide search, the housing department has not found someone to serve as deputy director for public housing, a position that has had an acting head for a year.

In the weeks to come, HUD, which has been reviewing the District's public housing operation since March, will make its own recommendations for change. Barry hinted that his response may be to invite HUD to play a larger role.

"HUD must do its fair share," Barry says in the housing report. "Currently, the District is carrying an unfair share of the financial burden for improving public housing conditions . . . as HUD reviews closely our public housing efforts, I would expect that, over time, HUD will begin to fulfill its fair share of public housing responsibilities as well."