GOV § 25683

This article does not authorize the imposition of any tax or special assessment on any property outside the county doing the flood control work whether the work is done directly by the county or by any district in, or agency of the county, nor the doing of any work pursuant to this article outside the county without the consent of the board of supervisors of the county in which the work is to be done if in unincorporated territory or of the legislative body of any city in which any of the works are situated in whole or in part.