AZ SB1533

Allows incorporated cities and towns to form improvement districts for acquiring, installing, and improving energy efficiency and renewable energy systems, including solar energy systems, combined heat and power systems, rainwater harvesting equipment, and gray water systems on public or private property.

Permits improvement districts to be formed when a petition signed by all affected property owners (or those subject to assessment) is presented to the governing body, with property owners allowed to join after formation by submitting a notarized petition.

Authorizes the governing body to levy annual assessments on properties in the district proportional to benefits received, with assessments collected through the same procedures used for general property taxes and delinquent tax collection.

Extends the same renewable energy and water conservation improvement authority to county improvement districts under similar formation and assessment procedures, with the requirement that any district including portions of a city or town must obtain formal approval from that city or town's governing body.

Prohibits cities, towns, and counties from requiring participation in these improvement districts as a condition of rezoning, development agreements, or other ordinances, and prevents districts from distributing or transmitting electrical power except through net metering systems.