Cal. Streets and Highways Code - SHC § 5180. Section 5180.
The legislative body shall make the expense of such work chargeable upon a district, which the legislative body shall, in its resolution of intention, declare to be the district benefited by the work, and to be assessed to pay the cost and expense thereof. The territory comprising said district may, but need not, include all, or be confined to, or extend beyond, the lots or lands fronting upon the improvement, or be contiguous, and the district may consist of separate and distinct areas or sections. The work performed in one section need not benefit the other section or sections.