Severe health problems, including to the neurological and respiratory systems as well as skin disorders, are inflicted on residents unknowingly living in a contaminated house.
Since he began testing for P in Wairarapa in September last year, Mr Nation said he had no more than "over a handful" of houses testing positive.
That was because his clients were house buyers who were getting the tests done for their peace of mind.
But he said another company he knew of that specialised in P testing was finding about 40 per cent of properties were coming up positive for the drug.
It was commonly rental properties that were used for cooking P, he said.
Mr Nation had heard numerous stories of people being caught out buying P-contaminated houses.
He said it was worth spending the $200 to $250 for the test at the outset to avoid any negative surprises further down the track.
Soft furnishings, like curtains and carpet, would be the first areas of the house to become contaminated by the drug.
The cost to repair the house depends on the level of contamination, Mr Nation said. With mild cases of contamination, a coat of specialised paint would seal in the chemicals. But in the worst case scenario, the house would have to be demolished.
Mr Nation said he anticipated methamphetamine testing would become a standard condition on sales and purchase agreements for people buying houses in New Zealand.
Signs a property could be tainted by P:
Chemical odours and dead vegetation around a section
An increase in visitors, combined with houses being outfitted with elaborate CCTV systems
Visible stains on curtains, walls and ceilings
Waste including empty medicine packaging, paint thinner containers and coffee filters with white or red substances
Tenants who only pay with cash.
