The secretary of the board shall cause notice of the filing of such petition to be given and published, which notice shall state the filing of such petition and give notice to all persons interested to appear at the office of the board at a time named in the notice and show cause in writing, if any they have, why the petition should not be granted. The board at the time and place mentioned in the notice, or at such time or times to which the hearing of the petition may be adjourned, shall proceed to hear the petition and objections thereto presented in writing by any person showing cause as aforesaid why the petition should not be granted. The failure of any person interested to show cause, in writing, as aforesaid, shall be deemed and taken as an assent on his part to the granting of the petition. The board may, at its discretion, accept or reject the petition. If it deems it is for the best interest of the district that the petition shall be granted, it shall enter an order to that effect granting the petition and from and after such order the irrigation district or persons therein shall be deemed to have acquired the water service as set forth in the order. If the petition is granted, the board shall determine the amount of money necessary to be raised by special assessment on lands within such irrigation district and shall certify to the county assessor, or county clerk where he is ex officio county assessor, of the county in which the lands of such irrigation district are located the amount of the assessment, plus a fair proportionate amount of the estimated operating and maintenance charges for each succeeding year on each tract of land and such county assessor shall extend the amount of such special assessment, plus the operating and maintenance charges, on the tax roll as a special assessment against the lands upon which the special assessment is made. Such assessment shall be paid and collected in equal annual installments over the period of years such water service is petitioned for as set forth in this section. If subdistrict or subdistricts are organized as herein provided, assessments of special benefits shall be made, spread on the tax rolls and collected in the same manner as herein provided in the case of irrigation districts.