Frequently asked questions

Within NSW, the sharing of available water is undertaken in accordance with the priorities for water sharing set out in the Water Management Act 2000 and the respective statutory water sharing plans for water sources. For the NSW Murray, Murrumbidgee and Lower Darling Rivers, the department must also consider interstate water sharing agreements and/or Snowy Hydro Scheme operations.

While the process for determining water availability and announcing available water determinations (typically referred to as allocations) is relatively straight forward, catchment conditions, climate variability, seasonal circumstances and a number of operational considerations can influence the allocation outcome. Nevertheless, the basic approach is outlined below.

Immediately prior to the commencement of the new water year on 1 July, the department calculates the minimum assured volume of water that will be available for allocation within each water source during the coming year.

This includes:

• how much water is available in the storages; plus
• a minimum natural inflow into storages (based on the historical record at the time of the first water sharing plan, being 2004 for many regulated river valleys); minus
• the volume required to run the river, including end of system flows, transmission losses and evaporation losses; minus
• other water sharing plan requirements, including storage reserves and credits to environmental water allowances; minus
• existing commitments, such as water to meet on-going high priority commitments including conveyance accounts and general security carryover.

When allocating water, the department is required to first ensure, as far as practicable, that two years of critical requirements can be met, before allocating to lower priority (general security) licence categories.

Water allocation guides have been prepared for major regulated river valleys in NSW and can be found at: How water is allocated

Today’s opening water allocations for NSW licenced water users reflect the ongoing favourable water availability in recent years. While some parts of the state have received below-average rainfall, much of the state received average to above-average rainfall over the past water year, contributing to regular inflows across river systems.

All critical needs, including local water supplies, are secure for the 2025-26 water year and all regulated river valleys have received their usual full opening allocation including for high security licences.

Most higher priority licence categories cannot carryover water; they forfeit unused account balance each water year. Therefore, opening water allocations are mostly about ensuring annual allocations are provided for all higher priority entitlements including local water utilities, domestic, stock and high security licence categories, particularly where account balances cannot carry forward into the new year.

General security users on all water sources have either received an opening allocation or have access to water allocated earlier (carryover) or both.

Supplementary access entitlements for all water sources, that have such licences, have received their full (100%) allocation for the 2025-26 water year, except for supplementary licence holders in the Lower Namoi water source. They receive a reduced allocation of 0.37 ML/unit share in response to required growth-in-use measures. Use of supplementary access account water can only be made during declared periods of supplementary flow.

It should be noted that water sharing plans require compliance with Long Term Average Annual Extraction Limits (LTAAEL) and that allocation to supplementary access licences can be reduced if LTAAEL is exceeded.

Rainfall in 2024-25 also reduced demand for groundwater and assisted the recharge of aquifers. All groundwater users have received a full allocation, apart from those (typically alluvial aquifers) linked to a surface water allocation.

Unregulated river access licences have all received their usual full allocations at the start of the water year. However, take is limited to specific river levels, including river levels below which pumping must cease to protect low river flows. Water access is only available when river flow conditions stipulated on water access licences are met. Therefore, under dry (low flow) conditions, unregulated river water users normally cannot take water regardless of their account balance.

As the water year progresses, regular assessments of surface water availability are undertaken. Improvements from inflows to storages following rainfall, as well as less than forecast transmission losses, are continually monitored so that any possible increases to water availability can be promptly announced. Allocations can continue to accrue if resources improve, up to the maximum allocation limits or account limits set out in respective water sharing plans.

Forecasts suggest the varied climate conditions experienced over the past 12 months, may continue for the first month or two of the new water year. While many parts of the state are expected to receive average rainfall, drier than average conditions are likely across the central and southern areas. However, the outlook improves from late winter to early spring, with above average rainfall likely across much of the state from August to October.

Wherever possible, further inflows will be captured, and allocations increased in line with the water sharing plan rules. The department takes a minimal risk approach when allocating water, particularly given the uncertainty around future weather and inflow conditions, so that water users can have confidence in the water allocated to their accounts.

For more information and regular updates on the climate outlook, please refer to the Bureau of Meteorology’s website.

Combined storage volumes for WaterNSW operated dams as at 24 June 2025 totalled about 11,000 gigalitres, which is around 60% of total active storage capacity.

The storage volume for major state-operated dams this time last year was approximately 75% full.

This shows a decrease of 15% in overall storage levels across the state compared with the same time last year, noting there are some variations from valley to valley, as reflected in the 2025-26 opening water allocations.

Water sources and entitlements that have received their maximum permissible allocation for the water year in accordance with the relevant water sharing plan, will not receive any further allocation until next water year (1 July 2026 for 2026-27). However, water allocation statements will continue to be produced quarterly for these systems, to keep water users apprised of seasonal conditions.

For water sources and entitlements that are not at their maximum permissible limit, typically general security entitlements in regulated valleys, resource assessments and allocation statements are generally issued monthly. If additional water becomes available, allocations are increased in line with the relevant water sharing plan rules. New water resources usually become available through additional rainfall and runoff over the course of the water year.

For information on the next regulated valley allocation update, please refer to the regulated water allocation statements on the department’s website at: Water allocation statements.

The available water determination (AWD) for Namoi supplementary water access licences was reduced at the commencement of the 2025-26 water year to 0.37ML/share. This AWD applies to all supplementary water access licence holders in the Namoi. The AWD defines the maximum volume that can be taken in that year prior to trades and is normally 1ML/share. However, the access to allocated water is subject to periods of declared supplementary flow.

The reduced allocation is required to address non-compliance with the long-term average annual extraction limit (LTAAEL). The Water Sharing Plan for the Upper Namoi and Lower Namoi Regulated River Water Sources specifies how this limit is calculated, how compliance is assessed and what action is required if there is non-compliance.

Growth in farm infrastructure has resulted in growth in total diversions and resulted in non-compliance with the LTAAEL. The water sharing plan specifies that the compliance action is to reduce the maximum available water determination (AWD) made on 1 July for supplementary water access licences. The required compliance action is to reduce total diversions to the LTAAEL.

Modelling is needed to determine the required action as the AWD impacts actual supplementary access diversions differently each year based on flow conditions and capability to store water. In many years there is no impact at all. See “What are the likely impacts?” for further information.

The assessment of growth has been based on the Namoi Source model. Results from this model were first published under the healthy floodplains program. We have continued to make improvements to the model. This led to an updated compliance assessment which will be published on our website.

See LTAAEL compliance results. Assessments for prior years are also available on the website.

Licensing of floodplain harvesting will address growth in floodplain harvesting above the limit (based on water use development that existed in 1999/2000). We will revise the compliance assessment after the commencement of these licences and publish an updated AWD if changes to allocations are required.

Our current information indicates that it is likely that restrictions on supplementary access AWDs can be relaxed after floodplain harvesting licences commence but will still need to be less than 1 ML/share. This is because floodplain harvesting licences will not address growth in total diversions.

There is no guarantee that the supplementary access AWD volume can be taken, as licence holders can only take water when a supplementary flow event is declared. This means that the maximum volume has no effect in the many years that have insufficient supplementary access opportunities for an entitlement holder to use their water and reach the limit. Supplementary events are declared when flows exceed the requirements set out in water sharing plans - typically when all other water requirements have been met. The reduced AWD does not impact on how these events are declared. Instead, it reduces the maximum potential volume that might otherwise have been taken in the water year. Trading of water can continue as usual.

The reduced AWD will not have any impact on licence holders in years when there are few supplementary flow events declared and hence little opportunity to take the maximum annual limit. The figure below uses historic usage data to show which years would likely have had impacts if the reduced AWD was in place. The orange bars show years that would have been affected.

Note that at the time of writing there was 32 GL of supplementary access usage in the 2024-25 water year in the Lower Namoi hence it is likely that there was no impact from the reduced AWD made at 1 July 2024. However, it is possible that individual entitlement holders used their full volume available.

We can't predict what the actual impact will be in the 2025-26 water year as we don't know what the supplementary access opportunities will be.

It is important to note that legal limits and our assessments against them are based on long term capability to take water. The way that we share water and check for compliance considers variable climatic conditions. This means that a growth-in-use management action can occur in wet or dry years. In any one year, water use can be above or below the long-term average limits. We assess compliance with the limit by comparing a model which reflects the limit to a model which reflects current conditions.

The models allow us to test what impact changes in infrastructure, rules or behaviour have on long term water use. Where we have metered water use, this is used to compare to the model. For LTAAEL compliance, what matters is that the valley scale total water use is reasonably reflected over multiple years; we don’t expect the model to match every year, and we don’t expect the model to perfectly reflect each individual farm.

Simple tests for trend in metered use are not sufficient to assess for compliance with the LTAAEL. This is because unmetered water use is not included and also because the growth in use assessment method needs to take into account how permitted take would vary given climate, water availability and water sharing plan rules. This variation can be complex. There is not a simple relationship between rainfall or flow and the expected permitted use in that year. For example, in a wet period there might be less metered water use as rainfall and unmetered use such as floodplain harvesting fulfill needs to a greater extent. Going into a dry period, there might be large amounts of metered water use if headwater storages have good supplies.

We have assessed growth by representing changes in the valley. The most significant change that drives the growth is increased infrastructure. For example, on farm storage capacity has grown by over 50% since 1994 which the Murray Darling Basin Cap is based on. Further information on infrastructure changes can be found in the Model Scenarios Report (PDF, 742.37 KB).