West Virginia started drug testing welfare recipients and the results were a total flop -- ThinkProgress.org

In 2015, West Virginia passed legislation requiring some applicants for Temporary Assistance for Needy Families (TANF) to submit to drug testing. The state estimated that over the first year, the program would identify 390 people as drug users at a cost of $50,000. ...
https://thinkprogress.org/west-virginia-drug-testing-welfare-6c426d9258af/