For purposes of this Article, the term "unit" means any of the following entities created pursuant to this Chapter: (1) A water and sewer authority created pursuant to Article 1. (2) A metropolitan water district created pursuant to Article 4. (3) A metropolitan sewerage district created pursuant to Article 5. (4) A metropolitan water and sewerage district created pursuant to Article 5A. (5) A county water and sewer district created pursuant to Article 6. (2020-79, s. 2.)