The board of trustees of the common sewer district, in its discretion, may create an advisory board for the subdistrict to consist of five members, each serving a term of two years. An authorized representative, not a member of the common sewer district’s advisory board under section 204.310, from the sewer subdistrict, together with the representatives of each county having territory within the subdistrict, may constitute the advisory board for the subdistrict. The board of trustees of the common sewer district may keep the subdistrict advisory board informed as to all phases of the planning and operations of the subdistrict, and the subdistrict advisory board may make such recommendations to the common sewer district advisory board as the subdistrict board deems advisable with regard to the construction and operation of sewers and facilities in the subdistrict.