Cal. Wat. Code § 55301
The board of supervisors of the county is the governing board of the district unless a board of directors has been appointed under the provisions of this chapter as they existed prior to their repeal at the 1967 Regular Session of the Legislature. Each member of an appointed board of directors in existence on the effective date of the amendment of this section at the 1967 Regular Session of the Legislature shall continue to serve at the pleasure of the board of supervisors of the county, rather than for the term for which he was appointed.
Where the district becomes a subsidiary district of a city pursuant to the District Reorganization Act of 1965, the city council of such city is the governing board of the district, as provided in Section 56539 of the Government Code. If, on the date the district becomes a subsidiary district of a city, there is an appointed board of directors, such appointed board of directors is automatically dissolved as of that date. The term "board of supervisors," as used in this division, shall in regard to any such district which has become a subsidiary district of a city, refer to the city council of such city.
Ca. Water Code § 55301