The board of agriculture shall have the power to fix and adjust rates and charges for the furnishing of irrigation or domestic water and for water service so that the revenues derived therefrom shall be sufficient to cover the cost of operation, maintenance, replacement, and debt service on revenue bonds in compliance with part III of chapter 39, and may make charges as may be necessary to cover the capital cost of the system or other costs incurred in connection with the system.

Nothing in this chapter shall be construed to prevent the board from selling water to persons other than land occupiers and other consumers within a water project in the event and to the extent that water in excess of the needs of the land occupiers and other consumers may from time to time be available.