Elections Code § 2027
ARTICLE 2. Determination of Residence and Domicile
The place where a person’s family is domiciled is his or her domicile unless it is a place for temporary establishment for his or her family or for transient objects.
Residence in a trailer or vehicle or at any public camp or camping ground may constitute a domicile for voting purposes if the registrant complies with the other requirements of this article.