FWIW- Where my wife works the temps are warmer than down there where you are and it takes months to taste funny. And then, even the funny taste is just plastic. I`m sure if we used the 'safe' nalgene bottles you wouldn't get that taste and could go all summer w/the same water.

Her biggest problem is not keeping the water fresh it's keeping the water in the car to go bad It gets used up then forgotten about!