In July of each year, the board of directors shall estimate and itemize all the administrative expenses and obligations of the district, including expenses of directors, expenses of operating the office, and any other obligations and liabilities relating to administrative, clerical, engineering, surveying, investigations, legal, and other related expenses of the authority. Upon the completion and adoption of such budget, the board of directors shall make a tax levy in an amount sufficient to meet such budget. Such levy must be in the form of a resolution, adopted by a majority vote of the members of the board of directors of the district. Such resolution must levy in mills, but may not exceed one mill, and must be sufficient to meet the administrative, engineering, surveying, investigations, legal and related expenses, obligations, and liabilities of the district as provided in the budget. The board shall also prepare and adopt an annual budget for operation, management, maintenance, and repayment of the southwest pipeline project. Revenues for operation, management, maintenance, and repayment of the southwest pipeline project must come from water service contract revenues.