2007 California Health and Safety Code Article 1. Generally

CA Codes (hsc:6830)

6830.  There may be annexed to a district any of the following
territory which is in the same county as the district or which is
within another county but in the natural watershed area of the
district:
   (a) Any territory contiguous to the district.
   (b) Any territory any point of which touches any point of the
district.
   (c) Any territory separated from the district by a "separating
barrier," which term includes a street, road, highway, railway line,
railway crossing, railway right-of-way, watercourse, lagoon, or other
natural barrier.
   (d) Any territory not contiguous to the district that will, in the
opinion of the district board, be benefited by inclusion in the
district.
   Any territory specified in this section may consist of one or more
separate parcels of land, but it is not necessary that all parcels
shall constitute in the aggregate one tract of land.