Salt credits: Hunter River Salinity Trading Scheme

Every 2 years, 200 new salt credits are created to replace expired ones. Credits have a lifespan of 10 years.

The new credits are sold by public auction, a process that can reveal the market value of credits. New industries can enter the scheme by buying credits at auction, or by acquiring credits directly from other scheme participants.

Although 200 new credits will be available every 2 years into the future, the total number of active credits is limited to 1,000. 

Environment protection at least economic cost

Licence holders can choose the most cost-effective strategy for their operation. This can be a mix of:

  • buying more credits; and
  • implementing cleaner technologies or practices (such as re-use or minimising the generation of saline water) so that fewer credits are needed.

The long lifespan of credits allows industry to plan ahead and adjust its processes over time. The result is that environmental outcomes are achieved at least cost to the community.

Credits determine who can discharge salt

There are a total of 1,000 salt discharge credits in the scheme and different licence holders have different numbers of credits. Licence holders can only discharge salt into a river block in proportion to the credits they hold: 1 credit allows a discharge of 0.1% of the total allowed.


If block 2023-198 can handle 112 tonnes of salt (the Total Allowable Discharge for this block), then a licence holder with 20 credits could discharge 2.24 tonnes (112 x 20 x 0.1%) into that block and a licence holder with 45 credits 5.04 tonnes (112 x 45 x 0.1%).

The licence holder performs a second calculation to determine what volume of their discharge water contains the permitted tonnage of salt.

Note: the Hunter River Register, available on the WaterNSW site determines when discharges can occur and the participants that are entitled to discharge during high flow river conditions.

Credits can be traded

The need for licence holders to discharge depends on highly variable operational conditions at each site. Credit trading gives each licence holder the flexibility to increase or decrease their allowable discharge from time to time while limiting the combined amount of salt discharged across the valley. 

An online trading system allows licence holders to trade quickly and simply. The trades can be for one or many blocks (for example, a single day or longer periods) and the terms of the trade are negotiated by the parties involved.

This credit register ensures the information on credit holdings is publicly available at all times. Other information on the trading scheme is also available.