Section 2101 Of Article 1. General Provisions From California Elections Code >> Division 2. >> Chapter 2. >> Article 1.

. (a) A person entitled to register to vote shall be a United States citizen, a resident of California, not imprisoned or on parole for the conviction of a felony, and at least 18 years of age at the time of the next election.
  (b) A person entitled to preregister to vote in an election shall be a United States citizen, a resident of California, not imprisoned or on parole for the conviction of a felony, and at least 16 years of age.