Locality Impact on GS 13 Salaries. Base pay for GS 13 federal employees is less than their total salary due to additional income from locality pay. This amount, which is determined by the physical location of the federal job, is paid in addition to base salary for every GS 13 employee.his process applies a specific GS rank to any non-executive federal job. The salary for a government employee is exclusively ascertained through the GS system. The average salary for a GS 13 employee ranges from $75,000 to more than $100,000 per year.