It's methamphetamine, commonly known as ice, and when smoked inside a home, it can stick there for a long time and cause terrible effects to the next occupants.

Bill Morris found all that out the hard way when trying to sell an investment property.

"We had a potential buyer, they paid the deposit," he said. "They signed the contract subject to finance and pest and building. I thought that was going to come back okay because we did pest and building every year.

"We were ready to exchange but the real estate agent said it fell through. They said 'the house is contaminated with methamphetamine' - I near fell out of the chair."

Mr Morris said the prospective buyers' conveyancer told them to test for methamphetamine. "I had no idea that was a thing," he said.

When exhaled, methamphetamine can stick to surfaces and recrystalise back into methamphetamine, which can cause skin irritation, flu symptoms, headaches and increased susceptibility to infections to current and future occupants.

This was all news to Mr Morris, who discovered that someone had been smoking ice in the house. The contamination was found to be above Australian guidelines, so the house had to be completely decontaminated before it could be sold or rented.

"We had to remove all the carpet, curtains, electricals, fans, lights, powerpoints even the dishwasher. It all went to the tip as contaminated waste. There was a lot of frustration."

Mr Morris said he was lucky the $50,000 bill was covered by landlords' insurance.

But his wife then suggested he get into the business of testing. So he went and did a course to become qualified.

Mr Morris, who has worked in the building industry for 40 years, set up his business Morris Meth Testing late last year and has since tested homes in Cessnock and Maitland.

He only conducts testing - not decontamination - as he said it would be a conflict of interest to do both, but for houses that return positive readings, he refers the customer onto several decontamination companies.

"All I want to know after that is when they are finished so I can come back and re-test," he said.

Mr Morris said any presence of the drug would remain a problem until it was dealt with. He found a study where a contaminated house was re-tested after four years and the contamination had not dropped.

He said the need for the service had grown with the rising use of ice. "This drug doesn't discriminate," he said. "And it's not like cigarette smoke - this stuff is invisible and there's no smell."