New Standards for drug contaminated properties

Thursday 6 July 2017

Authors: Belinda Green and Elena Chang

​​​​​​​On 29 June 2017, Standards New Zealand published NZS 8510:2017 'Testing and decontamination of methamphetamine contaminated properties' (the Standard). The Standard is a good start, but more still needs to be done.

Developed by a committee of 21 experts in the public and private sector, the Standard makes a number of key recommendations, including:

  • New acceptable contamination levels, which replace prior Ministry of Health recommendations.
  • Regulation of testing operators, their processes, qualifications, and reporting methods.
  • Decontamination and post-decontamination processes to determine whether the decontamination was successful.

The Standard does not have any legislative weight, so compliance is optional. But it's a good start for regulating the contamination testing and the decontamination process – particularly if the Standard receives a high level of buy-in amongst sampling and testing operators and decontamination contractors as it is expected to. However, there is still a lot of work outstanding in other areas impacted by contamination. These matters are not covered by the Standard, and our recommendations for residential landlords, prospective purchasers, and property owners are set out below.

What the Standard covers 

Decontamination levels

Methamphetamine contamination is obviously a significant public health issue and many people consider that any level of contamination is too much contamination​. However, there is general consensus amongst government agencies that very minor contamination residues may be acceptable.

The Standard sets out the following new levels which, if exceeded, mean that decontamination is required:

  • 1.5μg/100cm2 for high-use areas. A high-use area is any area in a property that can be easily accessed and is regularly used by adults and children so will include almost the entire house or building. 
  • 3.8μg/100cm2 for limited-use areas. These areas will generally be crawl spaces and wall cavities that don't contain services or ducting and are unlikely to be renovated.  

These new levels replace prior recommendations from the Ministry of Health and remove the different levels for properties in which drug manufacture or drug use has occurred. When announcing the Standard, Building and Construction Minister Nick Smith said that the new decontamination levels "results from a better understanding of the health risks"1​.  

Testing for contamination 

There are many sampling and testing operators in the market and home-testing kits are also available. The Standard makes recommendations which will regulate contractors in terms of the actual sampling processes and the recommended qualifications and forms of reporting. 

The Standard sets out information for two types of testing:

  • An initial screening assessment: Determines the presence or absence of methamphetamine contamination. This stage would be skipped if the presence of contamination is already known.
  • A detailed assessment: A thorough investigation of the property is carried out to determine the extent and magnitude of methamphetamine contamination. This is the assessment which will determine if the property requires decontamination. 

The Standard recommends that a detailed assessment only be done by those who are accredited under the relevant international standards (ISO/IEC 17025 or ISO/IEC 17020), while a screening assessment may be done by any trained screening sampler. Once the requirement for decontamination is confirmed, a decontamination scope of work should be prepared to set out the work required to reduce contamination to acceptable levels. 

Decontamination and post-decontamination actions 

The Standard sets out detailed recommendations for the decontamination process, including, for example, the removal and disposal of soft furnishings or other materials that may be difficult to clean. Following decontamination, further sampling will be required to determine if the decontamination was successful and a report (in the recommended format) should be produced for the person who commissioned the works.

What the Standard does not cover 

The Standard is a good start towards regulating an industry that has largely been unregulated to date. However, in terms of contamination testing and decontamination process, further work needs to be done to establish acceptable New Zealand qualifications for those undertaking the initial screening assessment, and for the creation of a public register which would allow property owners and managers to assess the qualifications of those they want to employ. Those looking to engage contractors should make enquiries about their qualifications and length of trading history, and obtain written confirmation that the Standard will be adhered to. 

There are also areas outside of the mechanics of testing and decontamination which need further consideration. These include: 

Residential landlords 

Landlords should have sufficient and clear legal abilities to test and manage their tenancies. These could include things such as conducting baseline tests at the start of each tenancy and ensuring that their tenancy agreements include additional terms which allow them to carry out regular tests throughout the duration of the tenancy. 

Given the differing views within the Residential Tenancy Tribunal, landlords may also wish to specify the level of contamination which will be acceptable at commencement and during the term of the tenancy. 

There are plans for the Standard to be incorporated into the proposed amendments to the Residential Tenancies Act, which should be considered by Parliament by the end of the year, which will address some of these issues. 

Prospective purchasers 

Prospective purchasers should satisfy themselves as to the presence or absence of contamination prior to purchase or make appropriate allowances for the risk of contamination. In this respect purchasers need to be aware that contamination will not always be noted on a LIM Report or on the Council's property file, and that real estate agents are only obliged to disclose the presence of contamination where it is known to them or they have a reasonable suspicion that there is a risk of contamination. Vendors generally have no duty to disclose the presence of contamination, but can be asked to provide information or warrant certain things are true. We recommend this as a prudent step for purchasers to test and rely on an owner's awareness whether a property has been used for methamphetamine manufacture or use. 

Further, purchasers who choose to carry out their own initial screening assessment should select a qualified contractor who is familiar with the Standard, and should be wary of relying on reports that were not commissioned specifically for them.  

Property owners 

Property owners have no obligation to report known or suspected methamphetamine contamination to the local Council. Obligatory reporting to government agencies is not particularly common in New Zealand, but we think this may something that the government should seek to legislate. 

In the meantime, owners may find that a note is added to Council files if, for example, the police or a neighbour reports the existence of methamphetamine manufacture and/or use with sufficient evidence. Under current legislation there is no formal ability for an owner to request a notation be removed from the LIM Report or property file, even if the property is completely decontaminated in accordance with the Standard. The best option is for an owner to keep the Council advised of any assessments or decontamination work and ask that these also be noted on the file or LIM Report.  

Ordinarily, Standards New Zealand charges a retail price for each standard that is published, reflecting the time and intellectual capital that goes into producing each standard. However, the issue of methamphetamine contamination has been identified as one of such importance to the public that Standards New Zealand has made a pdf copy available for free on their website (here). 

Please contact our team if you would like advice on any of the other issues raised in this update.​​​​


This publication is necessarily brief and general in nature. You should seek professional advice before taking any action in relation to the matters dealt with in this publication.

For more information
  • Andrew Petersen

    Partner Auckland
  • David Chisnall

    Partner Wellington
  • Elena Chang

    Senior Associate Auckland
Related areas of expertise
  • Real estate
  • Residential property