Recycled water the world over may not be safe enough to drink because it is usually tested for only one type of pathogen, said a Queensland University of Technology expert.

QUT bacterial DNA specialist Dr Flavia Huygens, from the Institute of Health and Biomedical Innovation (IHBI), is part of a team of scientists spearheading a new, innovative water testing technique to test for all kinds of pathogens, in hours rather than days.

"Pathogens can be bacterial, viral or parasitic micro-organisms like Cryptosporidium and Giardia which can make people sick if enough is ingested," Dr Huygens said.

"However, the traditional method for water quality testing is to look only for E. coli, an indicator of faecal contamination of the water supply.

"There is increasing evidence that questions the validity of relying solely on faecal indicator bacteria to assess health risks to humans, who either come into contact with contaminated water or ingest it.

"Pathogenic micro-organisms have been identified as the main human health risks associated with the reuse of treated urban stormwater, which is the runoff from paved and unpaved urban areas."

Dr Huygens said current water testing methods can take several days to yield results, but the test developed at QUT takes under five hours to complete.

She said only a single gene from any kind of bacteria, virus or parasitic organism could be detected, allowing scientists to determine what it was.

"The testing method, based on Polymerase Chain Reactions (PCR), allows us to magnify a pathogen's DNA to determine exactly what it is and how much of it is there," she said.

"This test is better than other methods, which can only determine whether or not a pathogen is present.

"When you know how much of a pathogen is present, you can determine how risky the water is to drink or use and you can also then judge the best ways to disinfect it."