What our sewerage says about Australia’s drug use

Alcohol and nicotine continue to top the list as the most used drugs in Australia, according to the latest National Wastewater Drug Monitoring Program (NWDMP) report.

Among the 12 drugs looked at in the report, cannabis was found to be the third most used drug in every region.

These trends are largely shaped by changes in Australia’s drug supply, the law, drug prices, and community influences such as location (e.g. access to certain drugs) and attitudes towards drugs.^1,2

In this article we look at the most recent wastewater analysis report published in August 2025, how it works, some trends, and what it can’t tell us about Australia’s use of drugs.

How does wastewater analysis work?

Wastewater analysis measures alcohol and other drug (AOD) use across Australia. It’s also used worldwide to monitor drug use in different countries and at events such as music festivals.

It looks at substances found in human waste, either in their original form or as chemically modified versions called metabolites (a byproduct created when the body processes a drug).

These substances enter the sewer system and are collected at wastewater treatment plants, allowing researchers to track drug use in areas covered by the sewer network.

Since 2016, the University of Queensland and the University of South Australia have been collecting wastewater samples to monitor drug use.

Samples are taken for one week every two months in capital cities, and every four months in regional areas.^1,3

What does the report tell us about drug use?

The report aims to provide a broad picture of drug use patterns across the country.

Sixty-one wastewater treatment plants took part in the study, covering 57% of the Australian population.

The sites were carefully selected to provide data on major population areas and to represent a wide cross-section of regional cities and towns.

The report mostly looks at drug use trends between April and August 2024 (with some trends examined up to October 2024), and provides comparisons on use in Australia:

• between and within states and territories
• between capital cities and regional areas.

The 12 substances examined in the report include:

• Alcohol
• Amphetamine
• Cannabis
• Cocaine
• Fentanyl
• Heroin
• Ketamine
• Crystal Methamphetamine
• MDA
• MDMA
• Nicotine
• Oxycodone.¹

What drugs do Australians use the most?

According to the wastewater data, Australians use alcohol and nicotine far more than any other drugs.

While alcohol use increased in 2024, nicotine use went down during the same period.¹

Cannabis is the third most used drug and is used at much higher rates than methamphetamine (includes ice and speed), which ranks fourth. It’s important to note the report can’t separate the use of medically prescribed cannabis and illegal cannabis.

It also showed that between 2023 and 2024, crystal methamphetamine (ice), cocaine, MDMA, and heroin use increased across Australia - which could be explained by a return to pre-COVID levels of drug use.¹

How does drug use compare across Australia?

Patterns of drug use are different between capital cities and regional areas, with some notable trends.¹

On average, people in capital cities used the following drugs more than those who live in regional areas:

• cocaine
• MDMA
• heroin
• ketamine.

While people in regional areas used more:

• alcohol
• nicotine
• MDA
• crystal methamphetamine
• oxycodone
• fentanyl
• cannabis.

How do capital cities compare to regional areas?

• Alcohol and nicotine: levels of use continue to be higher in regional areas compared to cities. This trend has been shown over the lifetime of the program.
• Cannabis: between April and August 2024, use of cannabis went up in cities and down in regional areas. But, from August to October 2024, use in cities dropped again, while regional use remained comparatively high.
• Crystal methamphetamine: showed big differences between regional testing sites, with some locations showing much more use than others. Use in capital cities decreased between August and October 2024.¹
• Cocaine: use was much higher in capital cities than in regional areas.
• MDMA: use was slightly higher in cities, although this has changed over time. Previous reports have shown higher MDMA use in regional areas.
• Heroin: use was much higher in capital cities. In many regional areas, heroin levels were too low to be detected.

Ketamine: between April and August 2024, ketamine use dropped in both cities and regional areas. But, from August to October 2024 use in cities rose to the highest levels recorded. Results varied widely across the country. Some testing sites had much higher levels than average, while others had very low levels.¹

What the wastewater data doesn’t tell us

The wastewater report provides valuable insights into drug use trends across Australia - but it also has limitations.
The report doesn’t provide a complete picture of drug use in Australia.

For example, the data can’t tell us:

• who is using these drugs
• how many people are using them
• why they are being used
• how they are being used.^{4, 5}

Increased levels of drug use could be explained by people who already use drugs increasing the amount they use, or by more people starting to use drugs. However, the wastewater data can’t tell us which.¹

Drug purity can change over time, but wastewater data doesn’t reflect this. So, an increase in reported drug use might also be due to stronger (purer) drugs, not more people using them.⁵

The report also doesn’t look at drug use on a day-by-day basis. This means it can’t identify any short-term changes in drug use. As a result, any rapid changes in the drug market, or use of emerging drugs of concern can’t be monitored.¹

Comparing data between different time periods in regional areas is also difficult, as testing sites can change locations.¹

In capital cities the same sites are typically used, making trends in these areas easier to track.¹

Overall, the wastewater report is best for understanding general drug use trends, rather than providing detailed insights about specific locations or groups of people.^4,5

While it can provide researchers and policymakers with an overview, it’s most useful when combined with other information to get a clearer picture of drug use in Australia.^4,5

Other ways to examine Australia’s drug use

In addition to wastewater analysis, there are other tools that offer deeper insights into Australia’s changing drug use.

• Drug checking (pill testing) in Australia is conducted through services like CanTest in Canberra, and The Victorian Pill Testing Service in Melbourne. These services allow people to anonymously and freely test the drugs they plan to use. They also publish ‘drug alerts’ when harmful substances are detected in the drug supply. These services help people to make more informed decisions around their drug use and let health authorities know when dangerous substances have entered the market.^6,7
• The National Drug Strategy Household Survey is a large-scale survey conducted every three years in Australia. It gathers information from over 21,000 people about their use and opinions on different drugs. The latest survey, conducted over 2022 and 2023, provides insights into changes in drug use and attitudes over the past 20 years.⁸
• Analysis of data on hospital admissions related to alcohol and other drugs offers insights on the harms associated with substance use at the state or territory level. For example, AOD Stats by Turning Point provides information sourced from across Victoria, including government departments, AOD treatment agencies, and Ambulance Victoria.⁹
• The Ecstasy and Related Drugs Reporting System (EDRS) and the Illicit Drug Reporting System (IDRS) are national illicit drug monitoring programs that look at drug trends in Australia. Both programs involve in-depth interviews with people who use drugs. The EDRS has been conducted in all states and territories since 2003, while the IDRS has been conducted every year since 2000.^10,11
• The Australian Secondary School Students Alcohol and Drug (ASSAD) survey, conducted every three years, examines drug use among adolescents aged 12 to 17. Involving up to 30,000 students, it provides insights into substance use across the country.¹²

The future of drug monitoring

Wastewater analysis focuses on measuring drug use rather than harms. On its own, it doesn’t provide the social or contextual information needed to inform drug policy.4

Combining approaches like wastewater analysis, drug checking, and other peer-led services is essential for creating policies that focus on people’s health, education, and reducing harms.4

The next National Wastewater Drug Monitoring Program report will be released in the first half of 2026.1

To learn more about the program’s latest report, you can read it here.