Scientists have been testing our wastewater. Here’s what it tells us about WA’s drug use

Western Australia’s regions continue to lead the nation for methamphetamine consumption, according to new data gathered through a long-running wastewater monitoring program.

However, there are few surprises in the latest report from the Australian Criminal Intelligence Commission, despite “record high” consumption of meth, cocaine and heroin recorded in the analysis.

The ninth year of the wastewater monitoring program took samples from seven sites in WA as part of the national survey, which covered about 57 per cent of the Australian population over a year from August 2024 to 2025.

ACIC chief executive Heather Cook said the results showed Australia’s illicit drug market was continuing to grow, driven by transnational criminal networks, and there was “persistent, elevated demand for major drugs” across the nation.

“Serious and organised crime groups continue to exploit Australia’s high demand environment,” she said.

“What we are seeing in this report is a stark reminder that Australia remains a lucrative target for transnational crime. The scale of the markets, reflected in the wastewater data, shows just how determined these groups are to maintain supply.”

Cook said high-risk stimulant use “remains a major contributor to national harm”, and burdened emergency service, families and frontline responders.

Cannabis remains the nation’s favoured drug, however a total of 15,791 kilograms of methamphetamine was consumed in 2024-25, according to the study.

Of that, WA consumed about 2145.6 kilograms, with the report noting: “Regional areas of Western Australia currently have the highest overall methylamphetamine consumption, while Adelaide, Melbourne and Perth generally had the highest capital city consumption.”

“A gradual increase over the past three years is apparent in almost every instance, reflecting the national trend,” the report stated.

It also noted the proportion of amphetamine relative to methamphetamine was increasing in some parts of the country – and increased diagnoses of conditions requiring amphetamine treatment could be behind the increase.

“It is recognised that amphetamine prescribing has increased in some jurisdictions due to increased diagnosis of conditions such as attention deficit hyperactivity disorder (ADHD) requiring therapeutic treatment with lisdexamfetamine and dexamfetamine,” the report stated.

“This is particularly the case in Western Australia.”

However, Dr Nicole Lee, an Adjunct Professor at Curtin University’s National Drug Research Institute, said the data did not necessarily reflect a growing drug problem in the west.

“The wastewater data tells us there is a lot of methamphetamine being consumed in WA,” she said.

“Other data like the population level National Drugs Strategy Household Survey tells us it’s not lots more people using, it suggests a smaller group of people are using more heavily and more often and more potent forms, which is exactly where the harm sits.

“If you look at other datasets alongside the wastewater, in regional areas, fewer people report using drugs, but those who do may be using more.

“Because wastewater picks up volume, not headcount, so it can make regional use look higher.”

Lee said the data showed there was still available supply and strong demand for a range of drugs in WA, despite the money and effort put into policing, “and we need to consider another way to manage the harms from illicit drugs”.

“We need to keep investing in treatment, early intervention and harm reduction, not just law enforcement as it’s not effective in reducing use or harms on any measure,” she said.

There were other gaps in the wastewater survey data, Lee said. It couldn’t differentiate quantity from frequency, nor whether changes are due to higher purity of drugs.

“So when we hear methamphetamine use is at a ‘ten-year high’, it really means the total quantity detected is higher, not necessarily that more Australians are using methamphetamine, or that harms are increasing,” she said.

WA’s drug use was not “a sudden surge”, Lee said, but an “entrenched market that has proven very resilient over time”, and which could be driven by a number of factors.

“Once a culture has embedded itself it can be hard to shift,” she said.

“WA is also close to where methamphetamine is manufactured around Asia and South East Asia.

“It’s a large wealthy state with among the highest salaries in Australia and we know that income is correlated with drug use.”

The report also revealed nicotine consumption had been rising over several years to reach the highest levels to date in the capital cities in October 2025.

“In regional areas, levels remained near historical high levels throughout the past year,” the report stated.

Lee urged caution in linking the rise in nicotine use to a boom in black market tobacco and vape sales that has challenged authorities across the nation and taken a chunk out of the amount of money the government received through its tobacco excise.

“It would be too strong to say wastewater proves this is the black market. But it is consistent with what we’re seeing,” she said.

“One of the known risks when access is restricted is that informal markets can expand, which can then increase availability across a range of related nicotine products.

“Again we can’t tell from the wastewater data whether current smokers are using more or whether there are new or returning users to the market.”

Lee said other data showed that among adults there was an almost straight swap of cigarettes to nicotine vapes.

“Depending on the vape, users may be getting more per puff from vapes than cigarettes which could account for some of the increase,” she said.

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