Cal. Harb. & Nav. Code § 6331

Bonds issued by any district pursuant to this part are legal investments for all trust funds, and for the funds of all insurers, banks, both commercial and savings, and trust companies, and for the State school funds, and whenever any money or funds may, by law now or hereafter enacted, be invested in bonds of cities, cities and counties, counties, school districts or municipalities in this State, such money or funds may be invested in bonds of districts organized pursuant to this part.