Recycling Water Bottles Too Often - a caution

[LtDan64]

First off, I may have put this in the wrong forum, and if so, please move it where you feel fit.
Right. I have heard that using the same plastic bottle too many times, (putting liquid in it, emptying, using more liquid, basically repeated rinsing of the bottle) can lead to chemicals in the plastic seeping into the liquids you are filling the bottle with. A friend I worked with warned me of this when I decided to keep refilling a more convenient 20 oz. bottle with the contents of 2L bottles (with a price difference of five cents per bottle). He said I shouldn't use the same bottle too many times, because he knew a friend who got sick once, and that ended up being the root of the problem.
That's about the extent of my knowledge on the issue, to be honest. What does anyone else know or have heard about this? Please post here.
I'm thinking it wouldn't be as much of a problem with using such bottles in water fights, (one doesn't normally lick the water off one's arms), but perhaps it might turn out to be a good precaution to use a different set of bottles each year. Again, if anyone knows more about it than I do (not hard), feel free to enlighten us.

[Dacca]

water is known as the universal solvent. over time, the polerized H2O atoms can break down pretty much anything with the exception of insoluble things. most plastics are insoluble and cannot be broken down by water due to their atomic structure (they're most often long hydrocarbon chains). what could be happining could be water mixing in things fixed to the plastic (impurities when the bottle was made) or the bottle could be soluble. either way it is still a good idea to not re-use bottle for an extended period of time, after all who knows what could get into the bottles and stuff.

[FinalFantasizer]

Your friend is right. It is for this reason that all professional chemical experimentation equipment (beakers etc.) is made of glass so that the contents are not affected by the container. That is also why coke that u buy in a plastic bottle has a diffrent taste than the kind u find in glass bottles. Just thought u should kno.

[isoaker]

Getting sick from re-using a water bottle is more likely due to life-based contamination such as bacteria as opposed to stuff leeching out of the plastic. So long as water isn't being left in the bottles for long periods of time, re-using them shouldn't be too much of a problem. Of course, if bottles are not properly dried, you increase the risk of growing bacteria, fungus, etc. that can cause problems.

Continual emptying and refilling, if you think about it, would technically be diluting the concentration of anything leeched from the plastic.