Va. Code § 58.1-3903
If the commissioner of the revenue of any county or city or the tax-assessing officer of any town ascertains that any local tax has not been assessed for any tax year of the three preceding tax years or that the same has been assessed at less than the law required for any one or more of such years, or that the taxes for any cause have not been realized, the commissioner of the revenue or other assessing officer shall list and assess the same with taxes at the rate or rates prescribed for that year, adding thereto penalty and interest at the rate provided under §§ 58.1-3916 and 58.1-3918. Interest may be computed upon the taxes and penalty from the first day following the due date in the year in which such taxes should have been paid and shall accrue thereon from such date until payment; provided, if such assessment was necessitated through no fault of the taxpayer, such penalty and interest shall accrue after thirty days from such date of assessment until payment.
Va. Code § 58.1-3903