In this article, unless the context otherwise requires "municipal water delivery system" means an entity that distributes or sells potable water primarily through a pipeline delivery system which is owned by either:
1. A city or town incorporated or chartered under the constitution and laws of this state.
2. A private entity which is regulated as a public service corporation by the Arizona corporation commission under a certificate of public convenience and necessity.
3. A special taxing district established under title 48, chapter 6.
4. An entity which is regulated as a water supply system by the department of environmental quality.