Bottled water shelf life under adverse conditions?

What is the shelf life of commonly available bottled water under adverse conditions? Say you throw a case of bottled water into the trunk of your car and leave it there for a couple of years. Will the plastic leach dangerous chemicals into the water? Are the bottles likely to survive multiple freeze/thaw cycles without rupturing? Assuming the bottles are protected from direct sunlight, is there any way the water could become dangerously contaminated in a non-obvious way?

Detail about what prompted this are in the spoiler box below for those who are interested.

[spoiler]A friend of mine works for a local agricultural service company. Most days, he is sent out in a company service truck and performs in-field tire swaps and repair of farming equipment. As part of his gear, he was required to always carry a two gallon jug of ice water so that he could stay hydrated out in the field. Apparently, the ice maker at the shop has failed beyond repair and his boss has declared that instead the insulated jug of ice water, they would just keep commercial bottles of water in the truck.

Now my friend does not work in an isolated, middle-of-nowhere location. He comes into town every day for lunch and usually at least once for parts. He has both his phone and a company radio for contact. It’s not that difficult for him to bring his own big cup of cold beverage (at his own expense of course). He’s unlikely to die of thirst out there. It’s annoying but on the surface, it’s not really a safety issue.

My thought is that these bottle will sit in the truck for months or years without being touched and by the time someone actually does drink one, they will have gone bad in some way that’s not clearly obvious. Is this a valid concern?

There is a 2014 study that tested 14 different brands of bottled water after putting them in high heat storage for four weeks. It found that one brand tested positive for antimony but at levels below drinking water standards.

Can not attest to the purity of bottled water, but water itself does not go bad
the water you drank today is billions of years old, you just recycled it again.

Stuff inside the water that is not water may decide to grow though
and i am not sure about what may leach out of plastic, nor how “sealed” the bottles are

My personal rule of thumb is that if it doesn’t make you want to vomit, drink it.

I’ll admit, I learned that rule while I was in college, maybe 40 years ago, but it’s served me will so far…

I think the main concern is with chemicals leaching out of the plastic into the water. And high temperatures are what makes this happen faster. I think how long it would take for this to happen would depend on the exact plastic used and the temperatures encountered.

The water supplies in Fallout Shelters were stored in polyethylene bags inside 55 gallon drums or cardboard tubes. We had some of these in my high school when I went there. They were pretty old even then, but I’m pretty sure that it stayed viable all that time. Maybe some plasticizer leached out, but not much, I’d think. They were supposed to be able to last 10+ years

Modern water bottles use Polyetylene terephthalate . As montioned above, small amounts of antimony can apparently leach out (how’s that even in there? Gota look up on plastic additives, because this isn’t one of the components of the poymer). There’s BPA in there, too, apparently, but this site says the amount that leaches out is negligible

From the spoiler:
Once a month take all the water out of the truck and put it into the office cooler from where the boss grabs his daily water bottles. Replenish the truck supply with fresh.

I’ve drank unopened water bottles from under my truck seat that have been there at least several months if not over a year. When really thirsty, it won’t matter.