Surety levels indicate the surety with which a water allocation can be expected to be available during a particular take period.
Each surety level has a notional availability attached. Notional availability is an estimated figure and is not a guarantee that the water will be there every year.
Where water restrictions are imposed, generally water allocations at a lower level of surety are restricted before restricting the taking of water of allocations at higher surety.
The hierarchy of levels from highest to lowest is as follows:
Surety 1 Water (expected to be notionally available at greater than 95% reliability)
- Rights for the taking of water for domestic purposes, consumption by livestock or firefighting under Part 5 of the WMA "Rights in Respect of Water" (i.e. no licence required);
- Rights of councils to take water for town water supplies (allocation at this surety level is two thirds of their actual daily usage in the five years prior to 2000 multiplied by 1.05 with the remaining one third allocated as surety 5).
Surety 2 Water
The water provision allocated to supply the needs of ecosystems dependent on the water resource.
Surety 3 Water
Commercial licences issued for a minimum of 99 years replacing old prescriptive rights under previous Acts.
Surety 4 Water
Rights of special licensees such as Hydro Tasmania. Special licences are granted to a body corporate for the generation of electricity or similar.
Surety 5 Water (expected to be notionally available at about 80% reliability - eight years in ten)
Rights issued for the taking of water otherwise than for the purposes described above under Surety levels 1-4. This includes rights for direct extraction, and for winter storage in dams, for use for irrigation or other commercial purposes.
Surety 6 Water (water allocations notionally available at a less than about 80% reliability)
Rights at this surety level issued for the taking of water for direct extraction for use for irrigation and other commercial purposes and for winter storage in dams.
Surety 7 Water (water allocations notionally available at a less than about 50% reliability, but greater than 20%)
Water allocations available with a lower level of reliability than a Surety 6 allocation. These allocations include water provided under catchment or site specific flow triggers and conditions.
Surety 8 Water
Water allocations available with a lower level of reliability than a Surety 7 allocation which includes water provided under catchment specific flood triggers and thresholds.