THE ESTIMATES of Maryland revenues keep shrinking as the time for budget decisions approaches. Maryland, like Virginia, the District and so many other places these days, is feeling a number of fiscal pinches all at once, stemming from national economic conditions that in turn are complicated by trouble in the banking, savings and loan and insurance industries, by the war, by the federal deficit and by consumer anxiety. The latest low numbers to show up are the sales tax receipts for January -- down 3.9 percent from their level a year ago -- and state income tax revenue, one percent lower than in January of 1990.

Gov. Schaefer already has ordered $353 million cut from what was to have been spent in the year ending June 30, with the budget for 12 months after that still in the air. The governor and the legislators agree that cuts are in order, but what about taxes? On this point, Gov. Schaefer has acknowledged what the lawmakers would rather not, but should: that some revenue-raising is essential. He already is pressing for a sales tax on the retail price of gasoline, which is the only way that any new highway or mass transit projects can get started in the next 18 months to two years. This is a tax that definitely should be enacted, but what about the availability of revenue for other programs in the budget?

The answer, Gov. Schaefer argues, is up to the legislature -- and can be mined in the pages of a report that few legislators in Annapolis are ready to accept whole but that many have found at least partially appealing. The Linowes Commission, appointed by Gov. Schaefer to examine the financial structure of the state, recommended all sorts of measures to raise and redistribute money. Legislators from Montgomery County, where higher incomes become primary targets of any move to make the income tax structure more progressive, couldn't be expected to like this report on a good day; with conditions what they are today, their arguments become even stronger.

Nevertheless, the governor decided to put the whole range of Linowes recommendations before the General Assembly and to tap Lt. Gov. Melvin A. Steinberg, a veteran of legislative politicking in Annapolis, to push what part he can. Administration aides have let it be known that the governor would like to work with the lawmakers on some compromise. Fair enough; there's nothing sacred about the recommendations. But the report is a valuable working document for a state tax system that has not been restructured in two decades and could stand adjusting. Similarly there are items that are not included in the base of the sales tax -- cigarettes, for example -- that could be.

It may well be that the legislators prefer to look the other way and take everything out in cuts; that may work, too. But if those grim revenue reports and revised estimates keep coming in as they have, the pressures for some better response are bound to increase.