For the purposes of this part, the following definitions apply:
(1) "Authority" means any regional water authority, regional wastewater authority, or regional water and wastewater authority organized pursuant to the provisions of this part.
(2) "District customer" means a county water and/or sewer district that is afforded the use or the availability of service from an authority.
(3) "Municipal customer" means a municipality that is afforded the use or the availability of service from an authority.
(4) "Public agency" means any municipality, county, water and sewer district, or other political subdivision of this state.
(5) "Rural customer" means a customer who is afforded the use or the availability of service from an authority and is neither a district customer nor a municipal customer.