Practical guidance for New Zealand
Meth testing, residue levels and completion evidence
Read results in context and understand what independent verification can and cannot confirm.
Guidance reviewed 7 October 2026. This is general property information; health, legal and insurance decisions depend on the circumstances.
What if I suspect meth use or manufacture but have no report?
Do not decide the cleaning scope from rumours, smells or a photograph. Ask for a suitable assessment and sampling plan. A swab finding meth residue does not, on its own, establish when it arrived, who caused it or whether manufacture occurred. A suspected laboratory can involve chemicals and other hazards beyond residue from smoking.
If you suspect an active or former clandestine laboratory, leave the area, do not handle containers or equipment, and contact Police from a safe place. For rental properties, the current rules specify circumstances requiring detailed testing, including certain Police or council notifications of manufacture and a valid screening result above the applicable limit. Use the evidence and property context to decide the next step.
Sources: New Zealand Police - methamphetamine and the law (opens in a new tab); Tenancy Services - meth contamination guidelines (opens in a new tab).
Screening, detailed testing and a useful report
Screening asks whether further investigation is needed; detailed testing helps define affected rooms and the scope. A useful report states sample locations and areas, collection method, laboratory method, individual or composite samples, detection limits, units, results and limitations. Results reported in micrograms per 100 square centimetres (µg/100 cm²) need to be interpreted using that sampling context, not treated as a measure of a person’s dose.
A home kit or pooled result may not identify the affected room or satisfy the relevant requirements. NIOSH field-composite sampling is not an approved rental screening technique under the 2026 rules; do not confuse it with laboratory compositing. Ask the tester to explain the method and its suitability. Detailed rental testing must be performed by a qualified professional independent of the decontamination. Paid screening also has competency and independence requirements. Check relevant competency and any claimed accreditation scope rather than relying on a generic badge.
Sources: Tenancy Services - testing and decontamination requirements (opens in a new tab).
Does a positive result mean a house needs cleaning?
Not necessarily. A positive result does not automatically mean every room needs decontamination.
A positive result does not automatically mean every room needs decontamination. The 2026 residential tenancy rules use 15 µg/100 cm² as the maximum acceptable level; the affected-area findings and valid testing matter. A result at or below that level does not by itself trigger decontamination under those rules. Above 30 µg/100 cm² is a separate threshold used for conditional tenancy-termination provisions, not the ordinary cleaning target.
The older 1.5 µg/100 cm² figure in NZS 8510:2017, the rental regulations and requirements in a contract are different contexts. Confirm which applies before agreeing work. A regulatory limit is not a personalised medical assurance, and a positive finding alone is not proof of injury. Owner-occupied, commercial and purchase decisions may need separate consideration of the evidence and written requirements.
Sources: Tenancy Services - meth contamination guidelines (opens in a new tab); Tenancy Services - testing and decontamination requirements (opens in a new tab); Government - 2026 methamphetamine regulations (opens in a new tab).
What confirms completion, and what if a result is still high?
For rental decontamination under the 2026 rules, independent detailed testing after the work must be carried out by a qualified professional. If residue remains above the applicable limit, further decontamination and testing are needed. Agree before work who books and pays for follow-up testing and what additional cleaning or repeat visits the contract covers.
Keep the original and post-work testing reports, sampling information, agreed scope, invoices and any completion record. The standard’s clearance report and certificate are not mandatory under the regulations, although another party may request particular documents. Neither a certificate nor a set of samples proves zero residue everywhere, medical safety or permanent protection from future contamination. Unsampled areas and the time of testing remain important limits.
Sources: Tenancy Services - testing and decontamination requirements (opens in a new tab).
Is testing compulsory between every tenancy?
No. There is no general rule requiring meth testing between every tenancy. The current regulations set circumstances in which testing and decontamination duties arise; valid evidence matters. If testing is arranged, the landlord must follow the relevant access and notice rules and provide results to existing tenants within seven days of receiving them.
Tenants can ask what was sampled, request relevant results and raise concerns with the landlord. A property history, screening assessment and detailed report serve different purposes. Check Tenancy Services’ current guidance before entry, using a result to end a tenancy or deciding that no further investigation is needed.
Sources: Tenancy Services - meth contamination guidelines (opens in a new tab).