NZQA Certified Samplers
Surface-residue sampling carried out by certified samplers holding NZQA Unit Standards 30892, 30893 & 30894.
When a property has been decontaminated after a positive meth test, the final step is meth clearance testing — also known as post remediation meth testing or verification meth testing. Meth testing after cleaning is an independent verification that methamphetamine residue has been reduced below the applicable threshold. Post-clean meth testing is not a formality; it is the evidence that the decontamination was effective and the property is safe to reoccupy.
Why Independent Clearance Testing Matters
The company that performed the decontamination has a vested interest in the result coming back clean. When the same company both cleans and tests for clearance, it is effectively marking its own work — and that creates a conflict of interest that insurers, tribunals, and property buyers may question.
EnviroCheck is an independent testing and advisory service only. We do not offer decontamination services, so our clearance testing has no commercial bias toward any particular outcome. This independence is what makes our toxicology reports defensible — for insurance claims, Tenancy Tribunal proceedings, and property transactions.
The Clearance Testing Process
Post-clean verification follows the same rigorous methodology as the original assessment. The process involves:
- Reviewing the decontamination report to identify which surfaces were treated.
- Re-sampling those surfaces using the NIOSH 9111 protocol — the internationally recognised sampling methodology required under NZS 8510:2017.
- Submitting samples to an IANZ-accredited laboratory for analysis.
- Comparing post-clean results against the pre-clean baseline to confirm the reduction.
- Issuing a formal clearance report stating whether the property meets the standard for reoccupation.
The applicable threshold depends on the situation: 1.5 µg/100 cm² under NZS 8510:2017 for non-rental situations (property sales, insurance, vehicles), or the relevant threshold under the 2026 Residential Tenancies regulations for rental properties.
When You Need Clearance Testing
Post-clean meth testing is required whenever a property has been decontaminated and needs proof that it is safe to reoccupy. Common scenarios include:
- After professional decontamination — to verify the cleaning was effective before tenants or owners return.
- For insurance claims — insurers typically require an independent clearance report before settling a meth contamination claim.
- For Tenancy Tribunal disputes — a clearance report is evidence that the property has been remediated to the required standard.
- Before re-letting or selling — to demonstrate to future tenants or buyers that the property is clean.
The Clearance Report
The clearance report is a formal, laboratory-backed document. It records the sampling methodology, the laboratory results for each surface, the applicable threshold, and a clear statement of whether the property meets the standard. This document is your evidence that the property has been remediated — keep it with your property records. For guidance on interpreting laboratory results, see our guide on how to read a meth toxicology report.
If your property has been decontaminated and you need independent clearance testing, contact EnviroCheck. We provide testing-only verification across New Zealand — no decontamination services, no conflict of interest.