Understanding Meth Reports
Plain-English help for property owners, landlords, property managers, buyers and sellers who need to make sense of a methamphetamine laboratory report — what the numbers mean, what to question, and what to do next. Understand your meth contamination report, meth testing report, and property contamination report.
This resource explains how to read and interpret a methamphetamine laboratory report. It is an educational guide — not professional advice, legal guidance, or a substitute for an independent assessment of your specific property. For methamphetamine contamination testing, book an independent EnviroCheck assessment.
What a Methamphetamine Laboratory Report Contains
A methamphetamine laboratory report — the document issued after surface wipe samples are analysed — should set out the laboratory's findings in a structured, verifiable format. A complete report typically includes the sampler's name and credentials, the date and time of sampling, the laboratory that performed the analysis, the analytical method used (in New Zealand, normally NIOSH 9111 under NZS 8510:2017), the specific locations sampled, and the methamphetamine concentration detected at each location expressed in micrograms per 100 square centimetres (µg/100cm²).
If any of these elements are missing or unclear, the report is harder to interpret and harder to rely on. Property owners, landlords and managers reviewing a report should be able to trace each result back to a specific surface, a specific method, and a specific laboratory.
Reading the Numbers — What µg/100cm² Actually Means
Methamphetamine contamination results are expressed in micrograms per 100 square centimetres (µg/100cm²). This is a surface-area concentration, not an airborne or whole-property measurement. A result of 1.5 µg/100cm² means that 1.5 micrograms of methamphetamine were detected on a 100cm² wipe area at that specific location.
Under NZS 8510:2017, the decontamination threshold is 1.5 µg/100cm² — if any surface exceeds this level, the property must be decontaminated before reoccupation. For rental properties, the Residential Tenancies (Managing Methamphetamine Contamination) Regulations 2026 set separate thresholds: 15 µg/100cm² (at or above which a rental property is considered contaminated and professional assessment is required) and 30 µg/100cm² (at or above which a rental property is considered uninhabitable). The 2026 regulations did not replace NZS 8510:2017, which remains the standard for non-rental situations such as sale and purchase decisions, insurance, and vehicles.
A single number on a page tells you very little without the context of where the sample was taken, how many samples were collected, and how the result compares to the rest of the property. Understanding meth test results means reading the number alongside that context — not in isolation.
Screening Results vs Detailed Assessment Results
New Zealand methamphetamine contamination testing is generally carried out in two stages. A screening assessment collects a limited number of composite samples to establish whether contamination is likely to be present. A detailed assessment collects a larger number of discrete samples to determine the location and extent of any contamination found.
A screening report that returns a low or non-detect result provides reasonable reassurance for a property with no specific risk indicators. A screening report that returns an elevated result usually requires a detailed assessment before any remediation decision is made. Confusing a screening result with a detailed assessment result — or acting on a single elevated screening sample without further investigation — is one of the most common and costly errors property owners make.
Common Issues That Make a Report Harder to Trust
Not every report is equally reliable. Three issues recur across the cases documented in Buried Truth: oversampling (collecting more samples than the situation warrants, inflating cost and the probability of a low-level positive), conflict of interest (where the testing company also provides remediation services, creating a financial incentive to find contamination), and ambiguous reporting (where results are presented without enough context to interpret them properly).
If the company that produced your report also offers remediation, or if the report does not clearly state the method, the laboratory, and the sample locations, it is reasonable to seek an independent second opinion before committing to any remediation work. Methamphetamine contamination testing should inform a property decision — not drive a commercial one.
Evidence Reports — Tribunal, Insurance, and Court-Ready Documentation
Not every meth testing report is the same. A screening report tells you whether contamination is likely present; a detailed assessment report tells you where and at what level. But when a report needs to carry weight in a formal dispute, it becomes something more — a Tenancy Tribunal meth report, a landlord meth evidence report, or an independent meth evidence report.
An independent meth report from a test-only provider carries more evidentiary weight than one from a company that also remediates, because the testing company has no financial incentive to find (or not find) contamination. For landlords pursuing a tenant for remediation costs, a landlord meth evidence report built on a pre-tenancy baseline and an end-of-tenancy exit test is the strongest possible documentation. For insurance claims, a meth report for insurance purposes must be NZS 8510:2017 compliant and independently produced.
In some situations — particularly contested tribunal matters or litigation — a court ready meth report produced through forensic meth testing methodology (NIOSH 9111 discrete sampling with IANZ-accredited laboratory analysis and full chain-of-custody documentation) provides the highest level of evidentiary weight. EnviroCheck produces independent meth reports designed for exactly these situations — we test and advise only, with no remediation conflict of interest.
The Toxicology Behind the Numbers
The thresholds on a methamphetamine laboratory report are not arbitrary. They reflect a toxicological judgement about how much surface residue may pose a risk to people living in a property. Understanding that judgement helps explain why a particular number matters — and why a single low result does not, on its own, mean a property is risk-free in every sense.
How people are exposed to surface residue
Methamphetamine residue left on surfaces can be taken into the body through three main pathways: direct skin contact with contaminated surfaces, ingestion through hand-to-mouth transfer (residue on hands is moved to food, toys, or the mouth), and inhalation of fine particles re-suspended from surfaces into the air. This is why surface-wipe sampling — not air sampling — is the standard method for assessing risk: the residue people may touch, ingest, or breathe originates on surfaces.
The Gluckman report and the threshold reset
In 2018, Sir Peter Gluckman — then the Prime Minister's Chief Science Advisor — reviewed the evidence on third-hand methamphetamine exposure (exposure to surface residue rather than active use or manufacture). The advisory concluded that the earlier 0.5 µg/100cm² guideline was not based on health-risk evidence and that low-level residue exposure posed a relatively low risk to most occupants. This review informed New Zealand's subsequent move to the current NZS 8510:2017 threshold framework, and it remains the most widely cited toxicological reference in the New Zealand methamphetamine contamination debate.
Why children and vulnerable groups are affected differently
Toxicological risk from surface residue is not uniform across all occupants. Young children are generally considered more susceptible for several reasons: they spend more time close to floors and surfaces where residue settles, they frequently put hands and objects in their mouths, and they have a lower body weight relative to the dose they may ingest. Pregnant women and individuals with existing respiratory or skin conditions may also be more sensitive. A result that may be of little concern for a healthy adult can warrant closer attention in a home with young children.
Acute exposure versus cumulative contact
A single high reading on a report may reflect a localised contamination event, while lower readings spread across multiple surfaces can indicate broader, cumulative contact over time. The toxicological concern is not only the peak concentration at one spot but the total surface area a person may come into contact with over weeks or months. This is one reason a detailed assessment — which maps contamination across a property — gives a clearer picture of actual exposure potential than a single composite screening result.
This section summarises publicly available toxicological discussion for educational purposes. It is not medical advice, a health risk assessment, or a guarantee about any specific property or occupant. Health concerns should be discussed with a qualified medical professional, and contamination concerns with a qualified independent tester. For the regulatory framework, see our guide to methamphetamine contamination.
Frequently Asked Questions
Where to go next
If you have a report you'd like independently reviewed, or you need a fresh assessment, start with our main methamphetamine testing page or contact EnviroCheck directly. You can also read more about the science behind methamphetamine contamination testing or the due-diligence framework for landlords and property managers.
This page is an educational resource. It does not constitute a professional contamination assessment, legal advice, or a recommendation about any specific property or report. All contamination concerns should be assessed by a qualified, independent testing professional.