A city in Washington State could be set to test its sewage for traces of cannabis in an effort to get a better idea of the amount of the drug used by residents. The author of Washington's recreational marijuana law has suggested that Spokane measure the levels of the cannabis chemical THC in the city's sewers to get a more 'honest' picture of usage. American Civil Liberties Union lawyer Alison Holcomb proposed the idea at a  meeting of the City Council's marijuana policy subcommittee. Cloned marijuana plants are pictured at the Sea of Green Farms growing facility in Seattle, Washington. In July, the first legal recreational marijuana stores opened for business in Washington state, making it the second state in the United States to allow the drug to be bought and consumed in a similar way to alcohol . A scientist for the University of Washington said the proposal is a good idea. 'It's always good for a chuckle, but it does actually work,' Caleb Banta-Green, a researcher at the University of Washington's Alcohol and Drug Abuse Institute, said yesterday. Mr Banta-Green has tested sewage in Oregon and Washington for the presence of illegal drugs like cocaine and methamphetamine. Ms Holcomb said  that testing sewage for THC provides a more accurate level of trends than self-reporting on surveys, in which people are asked about their drug use. She explained that people often give wrong information when questioned about drug use. 'We can expect to see more honesty' in the sewage, she said. There are many things to be learned from testing for the presence of illegal drugs in sewage, Mr Banta-Green added. Testing the sewage would provide a more accurate picture of the quantities of illegal drugs a community is consuming, he said. And testing over time would provide a picture of what days people are using, he said. A customer sniffs a strain of recreational marijuana at Top Shelf Cannabis, on July 8 in Bellingham, Washington, during the first half-hour of legal sales in the state . Mr Banta-Green's tests in Oregon, for instance, revealed that meth users tend to consume drugs daily, while cocaine users concentrate their use on weekends. In July, the first legal recreational marijuana stores opened for business in Washington state, making it the second state in the United States to allow the drug to be bought and consumed in a similar way to alcohol. Ms Holcomb said state policymakers are very interested in learning whether marijuana use goes up or down as a result of legalization. The City Council subcommittee meeting included representatives of schools, law enforcement agencies, nonprofits and local government to discuss what information needs to be collected as policymakers look to maximize marijuana revenue while ensuring public safety. Testing sewage, which can be frozen for later inspection, would provide only general use figures, not data broken down by age, Holcomb told the subcommittee.
American Civil Liberties Union lawyer Alison Holcomb proposed the idea .
She believes it will give a more honest picture of usage in  Spokane .
Says people often give wrong information when questioned about drug use .
In July Washington state opened its first legal recreational marijuana stores .
Policymakers  interested whether pot use goes up or down after legalization .
A city in Washington State could be set to test its sewage for traces of cannabis in an effort to get a better idea of the amount of the drug used by residents. The author of Washington's recreational marijuana law has suggested that Spokane measure the levels of the cannabis chemical THC in the city's sewers to get a more 'honest' picture of usage. American Civil Liberties Union lawyer Alison Holcomb proposed the idea at a  meeting of the City Council's marijuana policy subcommittee. Cloned marijuana plants are pictured at the Sea of Green Farms growing facility in Seattle, Washington. In July, the first legal recreational marijuana stores opened for business in Washington state, making it the second state in the United States to allow the drug to be bought and consumed in a similar way to alcohol . A scientist for the University of Washington said the proposal is a good idea. 'It's always good for a chuckle, but it does actually work,' Caleb Banta-Green, a researcher at the University of Washington's Alcohol and Drug Abuse Institute, said yesterday. Mr Banta-Green has tested sewage in Oregon and Washington for the presence of illegal drugs like cocaine and methamphetamine. Ms Holcomb said that testing sewage for THC provides a more accurate level of trends than self-reporting on surveys, in which people are asked about their drug use. She explained that people often give wrong information when questioned about drug use. 'We can expect to see more honesty' in the sewage, she said. There are many things to be learned from testing for the presence of illegal drugs in sewage, Mr Banta-Green added. Testing the sewage would provide a more accurate picture of the quantities of illegal drugs a community is consuming, he said. And testing over time would provide a picture of what days people are using, he said. A customer sniffs a strain of recreational marijuana at Top Shelf Cannabis, on July 8 in Bellingham, Washington, during the first half-hour of legal sales in the state . Mr Banta-Green's tests in Oregon, for instance, revealed that meth users tend to consume drugs daily, while cocaine users concentrate their use on weekends. In July, the first legal recreational marijuana stores opened for business in Washington state, making it the second state in the United States to allow the drug to be bought and consumed in a similar way to alcohol. Ms Holcomb said state policymakers are very interested in learning whether marijuana use goes up or down as a result of legalization. The City Council subcommittee meeting included representatives of schools, law enforcement agencies, nonprofits and local government to discuss what information needs to be collected as policymakers look to maximize marijuana revenue while ensuring public safety. Testing sewage, which can be frozen for later inspection, would provide only general use figures, not data broken down by age, Holcomb told the subcommittee.
'honest' picture of usage. American Civil Liberties Union lawyer Alison Holcomb proposed the first legal recreational marijuana stores opened for business in Washington state, making drug use. She explained that people often give wrong information when questioned about drug use. on weekends. In July, the first legal interested in learning whether marijuana use goes up or down as a result of legalization. The City