EVEN WHILE Washington's new mayor was underlining the necessities of municipal life for a nearly broke District of Columbia, her counterparts in neighboring Maryland and Virginia were tackling similar missions. Another newly sworn official, Montgomery County Executive Neal Potter, called for at least a 12 percent cut in all department budgets and sharp paring of the construction budget. Say what you will about the relative affluence of Montgomery, a scaling-down of services and public expectations of this magnitude entails rough adjustments.

Mr. Potter and the county council have the familiar limited ways to close any gap between revenues and spending: cut spending, raise revenues and/or ask for more money from the next higher level of government. Budget officials in Montgomery say Mr. Potter might accompany spending cuts with an attempt to raise revenues, seek more money from the state and reopen labor contracts to postpone pay increases. Without sufficient other revenues and pay adjustments agreed to by the unions, officials warn, the projected 12 percent spending cut might have to go as high as 17 percent.

Estimates of county revenues in the next fiscal year are grim; the general economic downturn throughout the region is affecting yields from real estate and income taxes. At the same time, Mr. Potter, who was elected on a wave of voter discontent with development, says he wants to change the way the county manages growth and development. He would limit new construction to 6,000 houses a year (8,000 were built in 1989) and new jobs to 9,000 a year (12,000 were added in 1989). The proposed construction limits drew immediate fire from school board members concerned about crowding and from others who have been awaiting completion of various road projects. Add to this Mr. Potter's statements that he is considering various taxes on development, and the complaints may become even louder.

The policy debates now beginning and the adjustments that will eventually be required will not help the popularity of executives or legislators anywhere. But a quick start on meeting the common demand for frugality is essential for all local governments around the region.