pour (something) down the drain

1. Literally, to dump out a liquid in a sink so that it travels down the drain. You can't pour cooking grease down the drain—it'll clog the pipes!

2. By extension, to squander or wastefully discard something. I can't believe that Jack poured all of our savings down the drain on his little gambling spree in Las Vegas. The candidate had gained a lot of support across the state, but he poured it all down the drain when he decided to drink and drive down Main Street.