This is an interesting study…
http://eastoregonian.com/main.asp?SectionID=13&SubSectionID=48&ArticleID=95522&TM=41256.42
Researchers are testing untreated sewage for chemicals that are found in drugs. From the article…
Scientists from Oregon State University, the University of Washington and McGill University partnered with city workers in 96 communities, including Pendleton, Hermiston and Umatilla, to gather samples on one day, March 4, 2008. The scientists then tested the samples for evidence of methamphetamine, cocaine and ecstasy, or MDMA.
Just wait until all waste water leaving your home gets tested. If they find traces of anything illegal it will give the Drug Enforcement Agency probably cause to storm your home. Ah yes, progress.
Source: http://www.schneier.com/blog/archives/2009/07/mapping_drug_us.html