Va. Code Ann. § 10.1-634

In connection with any referendum held pursuant to the provisions of this article, the directors shall also provide for the submission of the question involved to the qualified voters of the watershed improvement district and any question required to be submitted to referendum hereunder shall only be deemed to be approved, if approved both by vote of the landowners of the district as here above required and by a majority vote of the qualified voters of the district voting in such referendum.