Va. Code § 58.1-2025
If any tax-assessing officer or body authorized by law to assess taxes on any subject of taxation pursuant to this subtitle, ascertains that any property, or any other subject of state taxation which such tax-assessing officer or body would have been authorized to assess during any current tax year has not been assessed for any tax year of the three years last past, 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 thereon, for any cause, have not been realized, such tax-assessing officer or body shall list and assess the same with taxes at the rate prescribed for that year, adding thereto a penalty of ten percent, unless otherwise specifically provided by law, and interest at the rate established pursuant to § 58.1-15 which shall be computed upon the taxes and penalty from December 15 of the year in which such taxes should have been paid to the date of the assessment. If the assessment is not paid within thirty days after its date, interest at the rate established in § 58.1-15 shall accrue thereon from the date of such assessment until payment.
Va. Code § 58.1-2025