California Code, Water Code - WAT § 50704.5

When a parcel is held as community property or in joint tenancy or as tenants in common, any spouse or joint tenant or tenant in common shall be presumed to have authority to cast all votes for the parcel upon filing with the election board a certification under penalty of perjury identifying the spouse, joint tenants, or tenants in common for whom the votes are to be cast.  A legal representative, upon filing with the election board a certification under penalty of perjury identifying the principal and the authority of the legal representative, shall be presumed to have authority to cast all votes for the principal identified in the certification.