The Dictionary of American Slang, Fourth Edition by Barbara Ann Kipfer, PhD. and Robert L. Chapman, Ph.D. Copyright (C) 2007 by HarperCollins Publishers. Cite This Source
Idioms and Phrases with down the drain
down the drain
On the way to being lost or wasted; disappearing. For example, Buying new furniture when they can't take it with them is just pouring money down the drain, or During the Depression huge fortunes went down the drain. This metaphoric term alludes to water going down a drain and being carried off.
[ ; c. 1920