Dry cell (prison)

In prison terminology a dry cell is a room that prisoners are placed in that lacks any plumbing facilities such as a toilet or shower. In the Federal Bureau of Prisons, a dry cell can be used if a prisoner claims to be unable to urinate for a drug test under direct visual supervision. Prisoners are also sometimes placed in dry cells if they are suspected of having swallowed contraband. The idea is that they will eventually excrete all the contents of their digestive system, and lacking any toilet, they will be unable to dispose of it and thereby prevent prison officials from acquiring the evidence.