Whenever any territory in another county is annexed to a district it thereupon becomes a part of the district. The board of supervisors of the county in which is situated the annexing territory shall appoint one of its members to sit as a member of the board of directors of said district. All ordinances theretofore and thereafter adopted by the board of directors shall have full force and effect in all portions of the district regardless in which county the property is situated.
Source:
Section 4832.5, https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=HSC§ionNum=4832.5..