Meth contamination by the numbers

For years, New Zealand had no legal number for meth contamination. The informal guideline of 1.5µg/100cm² was the accepted standard recognised by testing companies and insurers.

The Tenancy Tribunal, Kāinga Ora and the Real Estate Authority apply a much higher threshold of 15 micrograms, based on scientific advice from Sir Peter Gluckman.

The situation meant properties were decontaminated that didn’t need to be and disputes reached the Tenancy Tribunal with no consistent standard to apply.

A change to the Residential Tenancies (Managing Methamphetamine Contamination) Regulations 2026 has put two hard numbers into law. That makes things clearer, though the problem landlords now face is that the insurance industry hasn’t necessarily adopted the new standard.

What counts as contaminated now?

The regulations set two thresholds, assessed room-by-room rather than across the whole property. Above 15µg/100cm², an area is legally contaminated and must be decontaminated before it can be re-let.

Above 30µg/100cm², the property is legally uninhabitable, triggering termination rights under section 59B of the Residential Tenancies Act: the landlord can end the tenancy on seven days’ notice, the tenant on two.

Below 15µg, nothing is legally required, which could shift the approach many landlords have taken in the past: treating any detectable trace as a reason to remediate.

Testing is now more procedural

The regulations distinguish between a screening assessment, which anyone can carry out, and detailed testing, which must follow an approved method to hold up in a dispute. A further rule closes an obvious conflict of interest: under the new framework, the company that decontaminates a property must be independent of the company that tested it.

DIY test kits remain useful as an initial screen, but results from non-compliant testing may not hold up if a dispute goes to the Tenancy Tribunal. Testing between tenancies is no longer a legal requirement either way, but that’s where the insurance gets tricky.

Insurers still reference old numbers

Insurance policies are contracts, not statute, and many haven’t caught up. Most major insurers still cap meth decontamination cover at around $30,000, and some policies continue to reference the old 1.5µg/100cm² guideline rather than the new legal threshold.

A property tests at, say, 8µg/100cm² – legally clean, no decontamination required – but remains outside what a particular policy will cover, leaving a landlord with a result the law says is fine and an insurer that disagrees. Potentially, thousands of previously insured losses could become uninsured events overnight as insurers recalibrate around the new legal line rather than their old one.

Process now matters as much as the result. Insurers commonly require a baseline meth test before a new tenancy begins and documented inspections every three to six months as conditions of cover. These obligations sit entirely outside the regulations, meaning a landlord can be fully compliant with the law and still void a claim on paperwork grounds.

Three key numbers

Reference point	Threshold
Old informal guideline (pre-2026)	1.5µg/100cm²	Still used by many insurers
New legal threshold: contaminated	15µg/100cm²	Decontamination required
New legal threshold: uninhabitable	30µg/100cm²	Termination rights, s59B RTA
Typical insurer decontamination cap	~$30,000	Shortfall is the landlord’s

What this means in practice

Test at the start of every new tenancy, even though the law no longer requires it. A documented baseline is what supports a claim later if contamination is found, and it’s what most insurers already expect. Use independent testing and decontamination providers, both because the regulations now require it for decontamination and because tribunal-grade evidence depends on it. And read the policy wording specifically for its meth clause – the actual threshold and cap – because the number that matters for a claim may not be the number that matters for the law. Expect this gap to close over time as insurers reprice around the legal standard, but until it does, the two numbers that count are the one in the regulations and the one in the contract, and they are not necessarily the same number.

Unsure about meth contamination and your rights as a landlord? Call us on 0800 GOODWINS.