Wastewater drug testing highlights variations across the country

Recent wastewater drug testing has shown that consumption of cocaine in NSW is as high as the rest of our other states and territories combined. Credit Jan Antonin Kolar image modified.

A few weeks ago we highlighted that another report from the National Wastewater Drug Monitoring Program had been released. The program, which essentially involves drug testing stormwater systems across Australian sites, provides an insight into the drug use of Australians and shifting trends.

An ABC article on the wastewater drug testing program provided an excellent insight about the differences between drug usage between the states, territories and regions. For example:

  • Consumption of cocaine in NSW is high. In fact, it’s so high that NSW people consume almost as much cocaine as the result of the states and territories combined. For the most recent report, cocaine consumption in NSW was estimated to be 1.9 tonnes.
  • The largest increase in cocaine consumption from this report to the previous report – despite NSW high use – was seen in WA.
  • In Victoria, they consumed close to half of all the heroin used in the entire country.
  • For Queensland, the drug of choice appears to be cannabis. They consumed more cannabis than another other state or territory, despite having less people than NSW and Victoria.
  • Interestingly, per capita, Sydney and Melbourne consumed less cannabis than other capital cities.
  • Adelaide was the biggest user of methamphetamine per capita.
  • On average, more methamphetamine was consumed in regional areas than in capital cities.
  • Tasmanians consumed nearly double the amount of MDMA – the active ingredient in ecstasy – in 2022/23 as they did the previous year.

Be careful what you read into the wastewater drug testing results

While the results from the wastewater drug testing provide a valuable insight into drug use and drug markets, it’s worth remembering that it does have limitations. For example, it can only estimate the overall consumption of a drug at a particular wastewater site. It can’t provide answers the questions such as who is using the drug, how many people are using the drug, why they use the drug and more.

This point is also highlighted in an article on The Conversation website. It highlighted that the most recent report mentions that consumption by weight of methamphetamine increased in 2022/23 from the previous year. This appears to contradict a recent study that showed use of the drug is falling and is at its lowest in a decade.

Why the contradiction? As explained by The Conversation, the wastewater drug testing program can’t tell us whether a small number of people have used a large amount of a particular drug, or many people using small amounts. It only provides an overall volume.

Surveys, like the National Drug Strategy Household Survey, which highlighted the drop in methamphetamine use, also have their limitations. While the survey is invaluable in providing more detailed data on drug use, it relies on participants reporting their drug usage honestly and accurately.

The Conversation says that generally people will forget or scale down their usage, particularly when it comes to illegal drugs. Therefore the results from surveys like this are perhaps an underestimate.

Yes, the wastewater drug testing program and the National Drug Strategy Household Survey are invaluable for providing insight into drug usage and markets. However, it is important to remember their limitations. That’s why it’s often best to look at the trends and long-term changes.


Recent wastewater drug testing has shown that consumption of cocaine in NSW is as high as the rest of our other states and territories combined. Credit Jan Antonin Kolar https://unsplash.com/photos/white-toilet-bowl-with-cistern-xXc7zUKIhRw (image modified).

By Michael

Michael is the founder of Integrity Sampling and is responsible for overseeing all national operations. He is based at Integrity Sampling's head office in Melbourne and is also responsible for the co-ordination of drug and alcohol testing within Victoria, assisting in the implementation of drug and alcohol (fit for work) policies and the presentation of drug and alcohol education and awareness programs. You can connect with Michael Wheeldon on LinkedIn

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