An analysis of Western Australia's sewage over the past year has confirmed the state's unenviable title of being the nation's biggest users and abusers of the drug ice.
The unusual method of testing sewage to measure methamphetamine use has only cost the WA government $40,000 so far but has also been the best scientific data collected about the problem to date, according to the state's police force.
The figures don't definitively show how many people use the drug ice but do back up a 2013 household survey that found 3.8 per cent of West Australians were users, Police Minister Liza Harvey says.
That is about double the national average.
Addicts are easily visible on Perth's streets and a senior WA judge Philip McCann recently said the state's ice epidemic was the worst in the civilised world and a disgrace.
The projected total consumption figure for WA based on the average Perth weekly consumption rate - 344.15 doses per 1000 people - was 2.098 tonnes which equates to $2.098 billion at street value.
That involved periodic testing of three out of Perth's five wastewater plants along with one each in Bunbury and Geraldton.
"Every member of the community should be shocked by the level of meth use in Western Australia," police Acting Deputy Commissioner Michelle Fyfe said.
She described meth use as a drain on police resources, that contributed to violence in the community and destroyed human lives and family relationships.
"It is not perfect and tells us the what, but not the why, but is scientifically proven, peer reviewed and accurate, there is nothing better than this data we have now."
Finding out the why was a priority, said Ms Harvey, who partly linked it to the extra cash in circulation during the mining boom.
She cited the extra $15 million the government had recently allocated to prevention and support to individuals, families and communities affected by meth and proposed laws to make rehabilitation compulsory.
"The reason? Obviously there has been a lot of money flowing through our community, there's a reason for the high usage rate in Western Australia and counsellors, educators and rehabilitation providers will help us with that."
The sewage testing was ridiculed when announced by some health workers and Labor Opposition Leader Mark McGowan, who called for more education campaigns and treatment services in remote areas.
Ms Harvey and Ms Fyfe defended the value of it, pointing out that following the arrest of a drug dealer in Bunbury, which recorded the highest ice use rates, there was a marked drop in usage.
When large seizures were made and there wasn't a drop in usage, that could indicate the drugs were due to go to other parts of Australia, confirming WA is used as a gateway to the east coast.
ICE IN WA:
* Wastewater tests indicate two tonnes of ice worth $2 billion consumed a year in WA
* In Perth 31.6kg of meth was used every week
* Police have seized 700kg of meth in the last 12 months
* About 1200 people were charged with 5000 offences
