Ala. Code § 11-88-42

Any authority authorized pursuant to this article may design or cause to be designed, contract for and execute or cause to be executed the construction or reconstruction of any improvement in its service area, and may cause the cost and expense of all or any part of any such improvement to be assessed against the property abutting on or drained, served, or benefited by such improvement to the extent of the increased value of the said property by reason of the special benefits derived from the said improvement.