Va. Code § 21-365
The owner of any land that has been assessed for the construction of any ditch, drain or watercourse as herein provided, shall have the right to use the ditch, drain or watercourse as herein let for lateral drains from the land; and if the land is separated from the ditch, drain or watercourse by the land of another or others, and the owner thereof shall be unable to agree with the other or others as to the terms and conditions on which he may enter their lands and construct the drain or ditch, he may file his ancillary petition to the court in such pending proceeding, and the procedure shall be as now provided by law. When the ditch is constructed it shall become a part of the drainage system, and shall be under the control of the board of viewers and kept in repair by them, as provided in this chapter.
Va. Code § 21-365