I generally carry a large water bottle (made of stainless steel, and insulated). I fill it with ice and water before I go out in the car, take it with me, then bring it back inside the house after the drive. I also have a few gallons in a plastic bottle in the bed of the truck. Mostly meant for emergency radiator fills (never had to use it for that), but could be used for drinking. It's just tap water. Probably stale, might have some of that plastic stuff leached into it, but not enough to be any kind of issue if I had to drink it in an emergency. Chances are, I could eat the entire plastic bottle itself and not ingest enough BPA/BPH/whatever to be of harm. I think concerns about these chemicals are way overblown for occasional/emergency drinking. Half the world's population would be dead already if the leached chemical problem were as bad as some make it out to be. One breath of air from inside your car on a hot day probably has more chemicals leached from the plastic/fabric in the car than a sip of water from a plastic bottle. Ever notice how the inside of your car windows need to be cleaned of that residue over time? You're breathing that stuff as well. Take reasonable care, but don't scare yourself to death worrying about it. Just my opinion.