Gov. Code, § 50591

Before the legislative body adopts an ordinance of intention to form the district, the superintendent of streets or other officer, board or commission of the local agency designated by the legislative body shall make and file with the clerk a preliminary report which shall contain the following information:

(a) A general description of the open areas proposed to be maintained, all of which must lie wholly within the boundaries of the district;

(b) A general description of the proposed maintenance;

(c) An estimate of the annual costs and expenses of maintenance of the open areas which benefit property within the proposed district;

(d) A diagram or map showing:

(i) The boundaries of the district proposed to be assessed and the public streets, alleys, ways or other public places situated therein;

(ii) Each parcel of land benefited by the maintenance, giving each a separate number or designation upon the diagram. The said diagram, as approved by the legislative body, shall govern for all details as to the lands determined to be benefited by the maintenance and to thereafter be assessed.

The preliminary report, prior to its filing with the clerk, shall be referred to the planning commission, if any, for its recommendation upon the formation of such district. The recommendation of the planning commission shall be transmitted to the clerk along with the preliminary report.