Sure, why wouldn't it be?

How long does it stay in your car before you drink it? It will be safe to drink but might not taste too great. Is it a sealed bottle of mineral water or filled from the tap?

Tap water has a tendancy to taste "flat" if left too long as dissolved gasses come out of solution. If you shake it pefore you drink it it should taste fine.

Having said that I keep a 2.5 litre bottle of water under the bonnet in case I need I need to top up the coolant or the washer bottle. That's been there for about 3 years & I prolly wouldn't drink that.

If you leave a bottle too long (that you have drunk from) you do run the risk of bacteria that have been transferred from when you last drank it would have multiplied a couple of thousand / million times. Therefore it would be recommendable to properly clean the bottle out every so often if you frequently drink from it.

Most of these bacteria are mostly "harmless" if you are a healthy person so if you really needed the drink your body would basically just deal with it. That's also the reason you should frequently clean the glass of water you put on your night stand, just refreshing the water won't do. As just as your keyboard, that glass of water you take to bed every night, is way up there when it comes to bacteria etc.

So if the bottle and the water were both "clean" when they went into the car and you didn't drink from it freezing it won't have any harmful effect on the water, with possibly the exception it'll taste somewhat flat.

Your body is surprisingly flexible when it comes to liquids. Unless the water is salty it will hydrate you. Of course you have to be careful with toxins and parasites etc but and even if water is undrinkable in some cases giving yourself an enema with this water will sufficiently hydrate you to survive.

I should really not watch to many of those survival programs on Discovery Channel!

The bottle is filled with filtered tap water and the bottle washed out when it needs refilling.

I was just curious as some foods can't be re-frozen but I couldn't find anything about re-freezing plain water.

Thanks,

Most food (especially meat products) contain small amounts of potentially harmful bacteria naturally (eg chicken contains salmonella), just in such small amounts that the risks are pretty much zero. The reason you can't re-freeze some foods is because once they reach temperatures above freezing point any dormant bacteria regenerate and multiply rapidly. This then means that your food, even if refrozen could contain hazardous levels of harmful bacteria.

I'm pretty sure that unless your water supply is tainted there are negligible levels of bacteria in it, and water treatment processes remove harmful ones so in theory you can defrost and refreeze water ad infinitum.

The bottle is the thing that is more likely to be harmful. Reused plastic bottles can start to release harmful chemicals after a time. I believe it's recommended that you only reuse them twice or something.

(Edited by Kate 10/03/2008 14:24)

If it's one of those hard PET bottles (like the coca cola ones) they're made to be reusable. I don't know about the one made from thinner material.

If you regularly use the same bottle, you should thoroughly clean it once in a while. There's not a lot for bacteria to grow on in tap water, and most of the bacteria in the bottle come from your own mouth, so you're not likely to get sick from drinking 'em, but it's better not to tempt fate