(2) If, after payment of all debts of the district, there remain any surplus funds to the credit of the district, such funds shall be turned over to the county treasurer of each county in which the district may be located, to become a part of the general fund of the county in the proportion that the assessed value of the property within the boundaries of the district in such county bears to the total assessed value of all property within the boundaries of the district as determined by the last assessment rolls.