The State Water Control Board refused yesterday to fund two major sewer projects in Fairfax County that, without aid, could cost the county up to $30 million.

The board's vote was part of its broad policy decision to shift the flow of money from Northern Virginia to other parts of the state that the agency claims are needier.

"We've got to fund secondary plants throughout the state before we fund advanced waste-water treatment, period," said board member Kenneth Rollins, mayor of Leesburg who is the architect of the policy.

Rollins said many localities throughout the state are still coping with sewer plants that provide only primary treatment and are frequently overloaded. On the other hand, he said, Fairfax and most of the rest of Northern Virginia have been able to improve their plants to an advanced treatment level.

In other action yesterday, the board also took $4.5 million in funds for advanced treatment at a Prince William County plant and shifted it elsewhere in the state.

To make that legally possible, the board also suspended tough new sewage effluent standards that the plant would be required to meet if it got the funding.

Both actions were actively sought by the Prince William Board of Supervisors, which has expressed concern about the cost of providing advanced treatment.

Suspension of the tough standards - whose purpose is to protect the poorly flushed shallow bays in the Potomac River where effluent is discharged - also will permit a private plant in Dale City to avoid making major improvements in its treatment capability. This too, was a goal of the Prince William supervisors.

Norman M. Cole Jr., former chairman of the Water Control Board, has been sharply critical of the board's decision to deemphasize advanced treatment. He has called the move cheaper than inferior treatment at scattered plants.

As a result of the board's action yesterday, Fairfax apparently will have to finance, out of its own funds, the Little Hunting Creek "pumpover" and the Difficult Run "pumpdown" - two projects that are expected to cost from $27 million to $30 million.