Cal. Wat. Code § 34577
After the transfer of documents pursuant to this chapter, the board of supervisors of the county to which the district is transferred shall have and exercise all of the jurisdiction, power, and authority over the district theretofore exercised by the board of supervisors of the principal county and any act or duty which is in this division required to be done by the board of supervisors or any officer of the principal county shall be performed by the corresponding board of supervisors or officer of the county to which the district has been transferred. After the transfer the district shall conduct and manage its affairs through its proper officials and in conjunction with the proper officials of each affected county as though the district was originally formed in the county to which it was transferred, which county shall thereafter be the principal county.
Ca. Water Code § 34577