Probably not as good for you as it might be. For relative context consider the water our ancestors drank. I've drank water out of a ditch and used a tube to pull it up from a crack in rocks and our ancestors did much the same thing.

Absolutely pure and absolutely safe would be great but I don't typically drink much bottled water so drinking a few liters of less than absolutely healthful water isn't a big deal. Simple fact is that health effects of drinking bottled water, even in the worse case, is so small that they need to concentrate the suspected chemicals and limit test animals to only drinking this mix to show any consistent effect.

Drinking a few gallons of bottled water during an emergency doesn't phase me. It also has to be pointed out that while PET bottles do leach tiny amounts of contaminates, if you buy bottle water in polyethylene containers, typically the larger one gallon and up milky looking containers, your exposure is essentially zero for the materials of concern.