Alabama Constitution of 1901, Art. XII, § 225.01

Obligations hereafter incurred and securities hereafter issued for any of the following purposes and under the following circumstances by a municipality having a population of less than six thousand inhabitants shall not be deemed to constitute indebtedness of such municipality within the meaning of section 225 of this Constitution:  (a) for the purpose of acquiring, providing or constructing sanitary or storm water sewers, or street or sidewalk improvements, the cost of which, in whole or in part, is to be assessed against the property drained, served or benefited by such sewers or abutting such improvements;  or (b) for the purpose of acquiring, providing or constructing school houses, provided that there shall be pledged for payment of the principal of and interest on such obligations or securities a tax which the governing body of such municipality shall have determined, upon the basis of its estimate of the revenues from said tax, will be sufficient to pay said principal and interest at their respective maturities.