One meth testing company has found methamphetamine contamination in 112 Tauranga houses in just over three years.
MethSolutions director Miles Stratford said the company was doing twice as many tests now as it was a year ago, but the percentage of positive tests was remaining around the 46 per cent mark.
"It shows you how common it is. While our numbers are up, the percentage of positive tests is not changing. This suggests we've got a long way to go."
Mr Stratford said he had positive tests at houses at all ranges of the socio-economic spectrum.
At one bank he dealt with, the average value of properties with significant issues was $600,000.
"Often, the perception is that it's a low socio-economic issue but that's not the case at all. It's at the top and the bottom of society."
Mr Stratford said Government research suggested meth use was increasing in New Zealand, but home owners were dealing with the consequences of use from up to 20 years ago.
"What we are dealing with is not just the consequences of meth-related behaviour occurring today, but over 20 years. That's why it's such a wide problem."
Mr Stratford said contamination was more common in rental properties.
If there was a check list for contamination risk assessment, the basic premise was that it could be anywhere, but if the home was a rental, the risk factor would increase.
The amount of contamination varied considerably, with some houses needing just a thorough commercial clean, while one house needed to be demolished.
"But that's the exception rather than the rule. From what we're sampling, many are well within health and safety guidelines and don't necessarily need further testing. But about half would benefit from additional testing being done," Mr Stratford said.
Tauranga Rentals owner Dan Lusby said drug contamination in rental properties was something he was aware of and concerned about.
Percentage of positive tests is around the 46 per cent mark.
The company carried out a basic drug test on all of the properties it managed between tenants unless the home owner asked them not to.
Mr Lusby said only one of the houses his company had managed had returned a positive test.
"The reason we tell tenants we test between tenants is just another way of saying, 'be careful because we are watching you and it won't be tolerated because it's breaking the law and it's making houses unhealthy for other tenants'."
Ministry of Business, Innovation and Employment tenancy services spokesman Paul Davies said landlords were required by law to provide reasonably clean and tidy premises at the start of the tenancy, and to ensure the premises complied with health, safety and building regulations.
"The Ministry also recommends that prospective tenants ask their prospective landlord if they are aware if the premises have been used for manufacture or use of methamphetamine.
"In this situation the landlord would be obligated to disclose any activity they are aware of ...
"A tenant may further make contact with their local council to discuss their situation if they suspect the premises is contaminated and may be a health or environmental risk."
On February 4, the Bay of Plenty Times reported that 26 Bay state houses had tested positive for meth contamination in the past 18 months.
