THE BUDGET CYCLE has started again: Mayor Washington has proposed a $1.4-billion budget for fiscal 1980, which begins Oct. 1, 1979. He says it would keep city services about the same without raising taxes. There are no new programs, but some agencies would get more staff and a bit more money. During the coming weeks, the City Council must decide what budget items should be changed, if any. Council members are somewhat reluctant to propose large changes in the budget, for no doubt they are waiting to find out what a new mayor may have in mind.

But there are some obvious deficiencies in Mayor Washington's budget, which the council should not ignore. For one thing, no money has been requested to fix up or sell the abandoned city-owned houses. Nor is any money set aside to help lower-income people make down-payments on homes - or pay increased rents. For that matter, there isn't even any money for additional staff already-swamped rent-control commission. Nor are funds to rid older buildings of lead-based paint in the budget.

Some very important items do appear in the budget, however. The Children's Center is scheduled to get some desperately needed renovation; D.C. General Hospital would get more staff. The Department of Human Resources (DHR) would be able to comply with recent court order to improve Forest Haven, one of the city's mental-health facilities. The Commission on Licensure to Practice the Healing Art would get staff and administrative money to discipline incompetent and corrupt doctors.

There are other items that may deserve closer examination. The Board of Electrons and Ethics, for example, is scheduled to get less money than was requested in last year's budget. And DHR would get almost 200 more staff people, although it is hard to believe that such a huge department needs to be even huger. But the most striking thing about importance: The mayor gives no indication of what programs need urgent attention. That makes the council's job all the more important. While the schedule for council review is tight, there is time for the members to examine this budget closely. They should take the opportunity to do so.