A. A county improvement district that has acquired, has constructed or owns a water system that provides domestic water to residents of that district or a county improvement district that has constructed and owns a wastewater treatment facility that serves the residents of that district may be converted to a district under this article by either of the following methods:

1. 1. A board of supervisors, by resolution, may order conversion of a county improvement district into a domestic water improvement district or a domestic wastewater improvement district after a public hearing conducted with not less than twenty days' notice mailed to the owners of real property in the county improvement district as shown on the most recent property tax assessment roll.
2. 2. The owners of at least fifty per cent of the property that is subject to an assessment to pay for existing improvements within a county improvement district may petition the board of supervisors for a finding and an order that the county improvement district be converted into a domestic water improvement district or a domestic wastewater improvement district, and after consideration of the petition the board, by resolution, shall order that conversion.