Sustainable diversion limits

There’s a limit to the amount of water that can be taken from the rivers for towns, industries and farmers in the Murray–Darling Basin. Each of the 29 surface water areas and 80 groundwater areas has their own limit.

• For many years, state governments managed water use through their own Cap on water diversions. A new system, known as the sustainable diversion limit, came into effect from 2019 and is binding on all states in the Basin.
• Water users are legally entitled to use all the water allocated to them by their state government.
• The amount of water available to allocate changes from year to year and depends on storage levels and weather conditions.

Water management in the Murray–Darling Basin is changing. As part of this transition, a new system of water limits begins, which replaces the ‘Cap’ system. This next phase is an integral part of implementing the Basin Plan.

The new system will focus on sustainable diversion limits, which limit how much water, on average, can be used in the Basin by towns and communities, farmers, and industries, while keeping the rivers and environment healthy.

Key facts

Limits are set for 29 surface water areas and 80 groundwater areas across the Murray–Darling Basin.

There are limits that guide how much water can be used in each area of the Basin. These limits consider climate, trade, usage patterns and development of infrastructure.

Sustainable diversion limits are how much water, on average, can be used in the Basin by towns, communities, industry and farmers.

Baseline diversion limits are an estimate of how much water was used in the Basin, before the Basin Plan.

The current system of entitlements and allocations continues under local water use plans and rules.

The water recovery target is a specified number in the Basin Plan.

Each area has a baseline diversion limit, which is an estimate of how much water was used in the Basin, before the Basin Plan. Initial limits were established under the Basin Plan in 2012. Limits need to consider the best available information and may adjust as new information comes to hand.

Water allocations and entitlements will continue to operate as usual under local water use rules.

The limits do not affect the water recovery target, as the target is fixed under the Basin Plan.

Different types of surface water in the Basin

There are 3 different types of water accounted for in the new system of limits:

• consumptive water
• held environmental water
• river water.

The sustainable diversion limit is focused on limiting consumptive water. River water stays in the river system or is lost through evaporation and seepage. Evaporation rates in the Basin are high, with 94% of the rainfall in the Basin being used by plants (transpired) or evaporating from the land and surface water.

Water usage patterns in the Basin are diverse. Usage year-to-year varies depending on climatic conditions, rainfall, trade, infrastructure development and individual business decisions.

The new system of limits will consider both the water available for use, the water expected to be used and the actual amount of water used. Water accounting occurs following the end of each water year.