EDITORIAL : GAMBLING, SACRAMENTO STYLE NEW BUDGET IS BALANCED ON SOME RISKY ASSUMPTIONS.

AT first glance, the $61.5 billion budget (those are the figures of the nonpartisan Legislative Analyst's Office) approved by the Legislature last week seems financially sound. That's because the $47.3 billion General Fund portion of the budget contemplates a $593 million balance at the end of the 1996-97 fiscal year and contains a $287 million reserve.

Appearances, however, can be deceiving. That's because this budget (as has been the case in the past) is based on some assumptions that might not materialize.

A report released last Wednesday by the analyst's office pointed out that the budget relies on federal actions to achieve $762 million in savings, mostly in health and welfare programs.

The new budget also assumes that Washington will provide $514 million to cover the state's costs of supervising undocumented prison inmates and wards of the Youth Authority.

If those assumptions aren't correct, California might wind up in the hole again.

Legislators and governors always should avoid approving deficit budgets that they know in advance will require borrowing (except for routine cash-flow purposes) to pay the state's bills.

Likewise, they should be careful about making assumptions that might not materialize. Thus, we would be more comfortable with the budget if it had a bigger reserve fund to cover unforeseen circumstances - such as the possible failure of Washington to deliver money that the state is counting on.