If a commission should realize a surplus over and above the amount required for the improvement, maintenance and operation of its facilities and for meeting all required payments on its obligations, it shall set aside such reserve for future improvements, maintenance, operations and contingencies as it shall deem proper and shall then apply the residue of such surplus, if any, to the payment of any recognized and established obligations not then due, and after all such recognized and established obligations have been paid and discharged in full, the commission shall, at the end of each fiscal year, set aside the reserve for future improvements, maintenance, operations and contingencies, as aforesaid, and then pay the residue of such surplus, if any, to the governmental bodies creating and establishing such commission in direct proportion to their financial contribution.