Va. Code § 21-211
If any city shall withdraw from the district pursuant to the foregoing provisions of this article, such city, if requested by the commission or the governing body of any county or town adjacent to such city, shall provide by its sewage disposal system for the treatment and disposal of sewage and industrial wastes arising in or discharged from such county or town upon such sewage and industrial wastes being delivered to such city, and shall agree with the commission or such county or town to treat and dispose of such sewage and wastes so delivered at the cost of such treatment and disposal, provided the commission or the county or town affected shall pay to the city the cost of installing any additional sewer main or mains necessitated thereby within such city. If the parties do not agree upon such costs, such costs shall be determined upon petition to the State Corporation Commission which is hereby authorized and directed to make such determination.
Va. Code § 21-211