An entitlement entitles its holder to a share of the available water resources in a water season.
The actual amount of water available to an entitlement holder in a season differs for regulated, unregulated and groundwater systems.
Regulated surface water systems are supplied from storages. The amount of water available to regulated entitlement holders depends on the amount of water in storage. The volume in storage is shared between entitlement holders using a system of allocations where entitlement holders are allocated a portion of their entitlement based on the storage volume.
Unregulated waterways are streams or rivers where the flow is not interrupted by dams or weirs, and the volume of water available for diversion is based entirely on rainfall and runoff. If the flow in the river is low restrictions may be placed on entitlement holders to restrict their take.
Groundwater refers to water found in underground aquifers, accessed by a bore. Depending on their location, groundwater entitlements may be treated similarly to regulated surface water entitlements where the amount of available water is determined by allocations; or, like unregulated surface water entitlements where the amount of available water is determined by restrictions.