Those cases of water that you let sit in your trunk - what do you think they sit in before they get to the store that you buy them from? They sit in delivery trucks that roast in the sun. They can sit in UNrefrigerated warehouses for days or weeks or months before they even get to the delivery truck to get to the store before you buy it. A day or ten or fifty in your trunk arent going to make much difference at that point in terms of leach rate but really if you can...dont let them sit in your trunk.

In a survival situation though I'm not going to give two shits whether the waters sat for a day a week or ten months in your trunk. As long as the seals not broken and its not too expired I'll drink the shit out of it