The Fairfax County Board of Supervisors, responding to dramatic increases in job turnover among public utility inspectors and complaints related to new building projects, approved a series of measures yesterday aimed at retaining experienced employes and reducing their workloads.

County officials said they hoped the steps, which include hiring additional personnel for the Department of Environmental Management and reviewing the salary schedule to see whether inspectors should be paid more, will help reduce complaints and speed the building plan review process at a time when construction is booming.

In other action during yesterday's meeting, the board:

Voted 5 to 0 to acquire 584 electronic voting machines, which officials hope will be in place by the March 8 Super Tuesday presidential primaries. County officials said the machines, which will be acquired through a five-year, $2.7 million lend-lease agreement, would replace all voting machines that were used in the county in the Nov. 3 election. The supervisors and numerous citizens complained that many of those machines broke down on Election Day and delayed vote counting.

Approved, on an 8-to-0 vote, an agreement with the Southeast Fairfax Development Corporation to address criticisms of the SFDC, a publicly financed group that is helping revitalize the Rte. 1 corridor.

Earlier this year, the SFDC was accused by a citizens group of barring people from its meetings, denying information to the public and generally siding with developers on controversial projects. The new agreement and changes to the group's bylaws state that citizens will be given additional seats on the SFDC board, that the board will notify the public of its meetings and comply with the Virginia Freedom of Information Act, and that board members will file financial disclosure forms.

In supporting additional staff and funds for the Department of Environmental Management, which conducts building inspections and reviews, and approves building plans, Supervisor Martha V. Pennino (D-Centreville) said employes of the department were "unsung heroes" for dealing with the huge workload.

According to a report to the board from County Executive J. Hamilton Lambert, the department's complaint branch has an "unprecedented" workload that has increased 77.7 percent between fiscal 1986, when there were 2,254 complaints, and 1987, when 4,006 complaints were lodged. About 6,000 complaints are expected this fiscal year, according to the report, which states that there have been no staffing increases in the branch since 1985.

The measure that was passed yesterday on an 8-to-0 vote with Supervisor Nancy K. Falck (R-Dranesville) absent will add 15 positions to the department. The staff increase should help reduce the workload, the report says. Initiatives such as putting air conditioning in inspectors' cars and producing a videotape training program should help reduce turnover, the report says.