Down the tubes
Wasted and unrecoverable.
Which tubes are being alluded to in this expression isn't known for certain. A strong candidate must be the soil-pipes which are connected to lavatories. The phrase is a variant of 'down the drain' and is the American equivalent of the British 'down the pan'.
All the early citations come from US sports reports, notably baseball. The earliest reference to it that I have found is in the Charleston Daily Mail, May 1954, in an interview with the world-record breaking Parry O'Brien talking about his reaction to an earlier collegiate record of his being broken by Don Vick:
"Yes, that gave me another incentive. I was proud of that record. Then I had visions of all my records going down the tubes."
See other phrases that were coined in the USA.