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How water is shared between states

Water is shared between New South Wales, Victoria and South Australia according to rules in the Murray-Darling Basin Agreement, which is part of the Commonwealth Water Act 2007. The Murray-Darling Basin Authority operates the river on behalf of basin governments according to these rules.

Watch this video to see how sharing works.

How much water South Australia gets

South Australia has an annual Entitlement of 1,850 GL under the Agreement. However, we do not receive the full amount every year; it can be reduced if water availability is limited when conditions are dry. In these years, South Australia receives a third share of all the available River Murray water.

Not all water available at the start of the year can be shared for allocation.

How it works

Each year, the Murray-Darling Basin Authority determines the volumes of water available for different uses, using this process:

  1. A certain amount of water is put towards system conveyance and storage losses for the current year, and then to the Conveyance Reserve for the following year. This water is used to “run the river”.
    South Australia’s portion, called the Dilution and Loss Entitlement, is 696 GL. This provides for losses in our state from the border to Wellington and ensures that water of suitable quality for human consumption can be extracted before it flows into Lake Alexandrina. This water is not available for allocation. The other states do not report system conveyance volumes in their water availability records, so it is difficult to compare.
  2. A certain amount is put to delivering water for critical human needs in each state. The volume required for critical human water needs is the minimum amount of water to meet:
  • core human consumption requirements in urban and rural areas
  • non-human consumption requirements; a failure to meet these would cause prohibitively high social, economic or national security costs (s86A(2) Water Act).

3. South Australia’s critical human water needs volume is up to 204 GL, of which 150 GL is for metropolitan Adelaide. Over one million people rely on water from the River Murray – in metropolitan areas, regional towns across much of the state and in towns along the River Murray itself.

The total available water for each state to allocate to individual water entitlement holders is determined. This is based on many factors, including the amount of water in major storages and the minimum amount projected to be available over the next 12 months.

The states may allocate their total available water to entitlement holders in accordance with state statutory water sharing plans. In South Australia, these are called water allocation plans.

As with other states, not all of South Australia’s Entitlement is allocated for consumption purposes. This is to ensure that there is enough water for river health.

Why is the process different in each state?

River Murray water is allocated differently in each state because each has its own management approach. Each state has unique water products, unique industries and different rules and requirements about how and when water is allocated.

Water sharing arrangements within each Basin state must comply with the rules and limits in the Basin Plan. Basin states must show how they are sustainably managing water resources in the Murray-Darling Basin by preparing and accrediting their Water Resource Plans. South Australia’s three Water Resource Plans are accredited.

To find out more about how water is shared between the states visit the Murray-Darling Basin Authority website.

View water resource availability to find out about current conditions and how much water is available.