Va. Code § 58.1-461
Every employer making payment of wages shall deduct and withhold with respect to the wages of each employee for each payroll period an amount determined as follows: Such amount which, if an equal amount was collected for each similar payroll period with respect to a similar amount of wages for each payroll period during an entire calendar year, would aggregate or approximate the income tax liability of such employee under this chapter after making allowance for the personal exemptions to which such employee could be entitled on the basis of his status during such payroll period and after making allowance for withholding purposes for a standard deduction from wages in accordance with the laws of the United States relating to federal income taxes and after making an allowance for any credit available to the employee as provided by § 58.1-332, and without making allowance for any other deductions. In determining the amount to be deducted and withheld under this article, the wages may, at the election of the employer, be computed to the nearest dollar.
An employer shall not be required to deduct any amount upon a payment of wages to an employee if there is in effect with respect to such payment a withholding exemption certificate, in such form and containing such other information as the Tax Commissioner may prescribe, furnished by the employee to the employer, certifying that the employee:
Va. Code § 58.1-461