Also it looks as if it has been blow moulded so therefore it would have to thermo plastic. HDPE would be the most likely candidate as it not shiny enough for ABS. The taste could be down to age and what has been put in there before -puritabs - sreech, as it is be hard to clean the inside of the water bottle properly.
edit to add
havn't you got better things to be doing then asking about the material composition of a water bottle? (yes, know this works both ways.)