California Code, Public Utilities Code - PUC § 99500

(a) Except as specified in subdivision (b), in addition to taxes imposed pursuant to Part 2 (commencing with Section 7301), Part 3 (commencing with Section 8601), and Part 31 (commencing with Section 60001) of Division 2 of the Revenue and Taxation Code, a tax of one cent ($0.01) per gallon (or, in the case of compressed natural gas, per 100 cubic feet thereof as measured at standard pressure and temperature) may be imposed pursuant to Section 99502 by a taxing entity, as defined in Section 99501, in the area which is under its jurisdiction and which is included in a county that has approved a proposition pursuant to Section 4 of Article XIX of the California Constitution.

(b) No tax shall be imposed under this chapter on fuel used in propelling an aircraft or a vessel.