Will very hot temperatures inside a car erode plastic bottles holding water?

I have some water stored in plastic bottles in my car. These are washed-out 2 liter soda bottles I filled with water from the tap. It is summer time and the temperature inside the vehicle seems to get really very high. Is storing the water in plastic in very hot temperatures something to be concerned about?

 

It depends on the quality of the plastic. Some plastics fade overtime due to exposure to heat. It is not advisable to keep plastics in hot environment because have seen situations where plastics kept in hot cars become melted.

 

As said above, it depends on the plastic. Take note, some plastics won't be harmful but if it is not pure plastic, you risk taking a contaminated water. And the bad side is you won't visibly see the harmful chemical.

 

In addition to what the others have said, the water itself is also affected by the heat. Specifically, it increases the amount of gaseous carbon dioxide in the water. That's why water has a tendency to get bitter after being warm for a long time.

 

We change the water stored in the cars regularly.
Extreme heat can cause the air in the top of the bottle to expand and leak out under pressure and when it cools again overnight the contents of the bottle will contract again causing a slight vaccume making the bottle appear crushed or melted.
Even though ultra violet light is useful for purification of water it will degrade some plastics very quickly, it's best to keep plastic bottles of water in a cool place out of direct sunlight. It was mentioned in a very thorough blog by Rambo that once opened stored water should be used up ASAP.