A new standard that targets methamphetamine-contaminated houses aims to guide landlords on testing and cleaning their properties.

Building and Construction Minister Dr Nick Smith said it was a "huge step forward" in helping home owners and tenants deal with the risks of meth contamination.

Smith said the most significant change was the 1.5μg/100cm2 limit, compared to 0.5μg/100cm2 under the old guidelines. He said the new standard resulted from a better understanding of the health risks.

"It will give people greater confidence and certainty, will result in hundreds fewer properties having to be vacated and save millions in unnecessary decontamination work."


Standards New Zealand manager Carmen Mak said the standard would make houses where meth had been found safer.

"Application of the standard will provide assurance that activities such as screening, sampling, testing, assessing, and decontamination of contaminated properties, and disposal of their contents, are carried out in accordance with good practice."

This comes as a Herald exclusive revealed some landlords with meth-contaminated houses are avoiding telling local authorities to ensure their houses don't lose value.

The investors say having the information on their property's council file - even if the chemical residue is later removed - carries stigma, and will put buyers off.

The NZS 8510:2017 Testing and decontamination of methamphetamine-contaminated properties targets P-labs, as well as properties contaminated by the use of methamphetamine.

Combined experience from 21 committee members in the public and private sector helped create the standard.

Standards development committee chairman Dr Mike Reid said it would provide a benchmark to those in the industry and aid in making homes safe to occupy.

"Nearly 1300 comments were received during the consultation period; the committee took all comments into account in the development of the final standard."

The standard will be used by methamphetamine testing and clean-up/decontamination companies; laboratories that analyse samples taken from methamphetamine-contaminated properties; health, safety, and environmental regulators; property owners, managers and insurers.

The standard can be downloaded from the Standards New Zealand website.