New Zealand Law Society - First wastewater testing results show drug use patterns

First wastewater testing results show drug use patterns

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The New Zealand Police has released results of the first three months of a national programme to test wastewater for drugs.

The drugs that have been tested for are methamphetamine, cocaine, heroin, MDMA and fentanyl. The testing covers around 80% of New Zealand's population.

The results, for November 2018 to January 2019, found average weekly use of the detected drugs had an estimated street value of $9.6 million. The Police say this is estimated to generate "approximately $500 million of criminal profit" annually.

Information provided by the Police on the programme does not appear to outline how values or profits are estimated. Details of the results for each of the Police Districts are available here.

Police Minister Stuart Nash says the expanded testing programme is still in its infancy and care must be taken with reading too much into the results of the testing, between November 2018 and January 2019.

"However, it is clear that methamphetamine use, and the organised crime syndicates behind its distribution, need attention," he says.

“The programme was initially a pilot in three sites but $1 million was set aside in last year’s budget which enabled it to be rolled out to 37 sites nationwide. It tests for methamphetamine, MDMA (ecstasy), cocaine, heroin and fentanyl.

“The wastewater testing cannot pick up traces of synthetic drugs, nor is yet covering cannabis use. The programme tests public sewage schemes for traces of restricted drugs, to provide insight into patterns of use."

Results as summarised by New Zealand Police:


  • Methamphetamine remains the most commonly detected illicit drug nationwide, with approximately 16kgs consumed on average each week.
  • Detected average methamphetamine use translates to an estimated $20,606,002 per week in social harm. Annually, this could equate to $1,071,512,099.
  • Methamphetamine use is most prevalent per capita in the Northland Police District, followed by Eastern District (Hawke’s Bay). Tasman and the Southern Districts had the lowest prevalence per capita.


  • MDMA was the second most commonly detected illicit drug across the country, with an estimated consumption rate of 4kg on average each week.
  • MDMA use is most prevalent in Canterbury District, closely followed by Southern District (Southland). Central and Northland Districts had the lowest prevalence per capita.


  • Cocaine was detected in low quantities, approximately 700g on average each week. This indicates a much smaller user base and likely reflects less demand and supply associated with the drug.
  • Cocaine use is significantly more prevalent in the Auckland region (per capita) than anywhere else in the country. Eastern, Northland and Tasman Districts had the lowest prevalence per capita.


  • Overall Fentanyl consumption averaged less than 3g per week.
  • The apparent prevalence of fentanyl in Northland District, compared to other districts, must be viewed with caution as detected average usage across all testing sites is extremely low.
  • The aim of testing for fentanyl is to establish a baseline of consumption so, over time, Police and the Ministry of Health can determine any fluctuations in the consumption. A baseline for consumption remains unclear at present.
  • As fentanyl has only been tested for very recently, it is too early to draw conclusions about what proportion of the fentanyl in wastewater is illicit. 


  • Heroin was not detected at any of the testing sites between November 2018 and January 2019. This is consistent with other indicators that the opiate user population in New Zealand is very low.
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