What sort of businesses will be required to pay for their water?

All commercial water users will pay, including electricity generators.

 Commercial water users will be required to pay for their entitlement rights (which gives them the first right of refusal to use water at the market price) and the per unit use price. IF a commercial water user doesn’t have an entitlement right they can still access any water left over after those with entitlements take their share, but they still pay the per unit market price.

 Hydro dams will need an entitlement to use the water, but will only pay a per unit charge for the water that is lost in their dams via evaporation.