A spike in the number of Kāinga Ora homes being decontaminated for methamphetamine is thought to reflect a growth in New Zealand’s meth issues.

The social housing provider has spent about $1.8 million decontaminating 56 houses, between July 1 and November 6, data released to Stuff under the Official Information Act shows.

That’s a busy four months, looking at the social housing provider’s past four years.

In the 2019-20 financial year there were 135 properties decontaminated. The number dropped to 64 in 2020-21, but climbed again to 119 in 2022-23.

Kāinga Ora general manager national services Nick Maling said there seemed to be a spike in the number of decontaminations this year, which reflected the growth of meth issues in New Zealand.

The drop to 64 in 2020-21 reflected Kāinga Ora’s adoption of a higher level of acceptable meth contamination levels, Maling said.

Here is a by-the-numbers breakdown of Kāinga Ora decontaminations.

0

There were no demolitions of Kāinga Ora houses contaminated by meth this year. Maling said properties contaminated with meth did not need to be demolished any more, thanks to modern decontamination methods.

“Chemical cleaning of meth residue is safe, relatively affordable and highly effective at returning the home to a liveable standard.

“The last known demolition in our records due to meth contamination levels was in 2018.”

0.000015 grams

The habitability threshold adopted by Kāinga Ora was 15 micrograms of meth per cm² of surface.

Maling said the agency adopted the threshold after the release of the Sir Peter Gluckman report in 2018, which recommended thresholds 10 times higher than the national standards.

“In the rare occurrence where manufacture [of meth] has been discovered, the testing threshold of 1.5µg/100cm² is used,” Maling said.

“While these initial testing thresholds were changed, any home that is found to contain contamination above the relevant threshold is still decontaminated to below 1.5µg/100cm² in line with the New Zealand Standard.”

4 days

It normally took about four days to get a meth contamination test result.

Extreme Cleaning Solutions director Astrid Herbert said for a 120m² house the chemical decontamination process took two days, after which air was blown through the rooms by a machine, and the house was aired for three days.

She said the house would be tested for meth contamination before and after decontamination.

Maling said Kāinga Ora currently worked with three approved decontamination partners: Hygiene Pro Clean, Extreme Cleaning Solutions, and Fresh Living NZ.

Gavin Bush, a meth tester in Hawke’s Bay, said the laboratories were finding results had higher levels of meth contamination than in previous years, although the number of houses being tested had reduced since he started in 2015.

Bush, who was also chairperson of the New Zealand Association for Contaminant Free Properties, said it was rare to test houses with a level of contamination above the habitability threshold six years ago.

“Now it’s not rare, it’s common,” he said.

A contaminated house would have no strange smell. In fact, Bush said, the contamination would be odourless.

$39,155

On average, each property decontaminated in the past financial year cost Kāinga Ora $39,155.

72,000

Kāinga Ora was the largest single landlord in the country, owning about 72,000 properties.

“The number of properties requiring meth testing and decontamination work, and the cost of this work, is relative to the size of our housing portfolio,” Maling said.

$5.9m

Kāinga Ora’s budget for decontamination in the financial year 2023/2024 was $5.9m. The funds covered meth testing, decontamination and reinstatement of a property.

In the 2026-2027 financial year, the budget would grow to $6.6m.