Ala. Code § 11-50A-11
When payments required by the provisions of Section 11-50A-17 to be made by any municipality authorized to contract with the authority pursuant to Section 11-50A-17 are pledged as security for the payment of bonds sought to be validated, the petition for validation shall make parties defendant to that action every municipality which has contracted with the authority for the output, capacity, use or service of the project for which bonds are sought to be validated. Notice to the taxpayers and citizens of such municipality shall be made as provided in Section 11-81-222(d). Every other party, public or private, contracting with the authority in any manner with relation to the construction, ownership or operation of the project for which bonds are sought to be validated may also be made parties defendant to that action.
Ala. Code § 11-50A-11 (1975)