I carry a Dasani bottle around with me wherever I go. It has become my close friend. When it’s empty I fill it as necessary. If it doesn’t get empty, I don’t fill it (well, sometimes I put a head on it. I guess the point is that i don’t empty it and refill it with fresh stuff).
Is this bad? Can bad stuff grow in it overnight or even in a few days? Remember, this is a bottle with a cap, not an open glass. Does that matter?
I do the same thing, and I’ve never had a problem. Most dangerous micro-organisms grow slowly at room temperature, and none will grow at all without a source of carbon. If the water is clean, microbial growth is unlikely.
Plenty of nasty (and not-so-nasty) micro-organisms function anaerobically, so capping will not prevent growth, but it will prevent airborne contamination.
I’ve always thought of it this way: ancient man used to only drink water that had been sitting for days (or more), in lakes and ponds, which are seething with organisms and bacteria. How bad can leaving water in a bottle (especially capped) for a while be?
The water should be fine. This is assuming a couple of things though. Fist assumption is that you are getting your water from a clean source. The other is that you empty the bottle on occasion.
The clean source question should be obvious, but alas is not. My sister had well water that smelled a bit odd. So I took a sample and tested it in my lab and it was full of coliforms. Apparently the well was to close to the septic field, and her well water did not meet EPA standards for potable water. City water on the other hand, should be OK. A good rule of thumb is: If it smells funny don’t consume it.
Even clean water has the potential to create a biofilm after extended periods of time. This is the slimy stuff you find on the side of a dogs dish.
My suggestions is that you either thoroughly clean or replace the bottle once a week. You can keep it longer if the water is generally kept refrigerated.
My major problem with this line of reasoning in health-related arguments is that ancient man didn’t have a particularly long life expectancy (in the low 40’s, IIRC, not counting the high infant mortality). I don’t really want to emulate their behavior, seeing how it got them killed by stuff like contaminated water.
I am not a doctor and I can’t prove this:
I think that bacteria get in the clean water from your mouth when you drink. If you let the water sit at room temp for a few days the bacteria will multiply. I know that it will make you sick if you were healthy. But, if you have been sick I would get a new bottle and fresh water. (Aren’t you suppose to get a new tooth brush when you have been sick to prevent getting sick again?)
I think that the slime in the dog-water comes from the bacteria in the dog’s mouth.
I think at the very least it would taste pretty rank.
I don’t know if I should post this response, as I have no cites to back it up, but my SO does work for a large water and sewer department, and I have asked him this same question. I interpreted his explaination like this:
The stuff used to keep the water clean (chlorine? I think some water treatment facilities use ozone, but I don’t know how that works) deteriorates over time and with exposure to light.
If there are minute amounts of bacteria in the water that comes from the tap, or if bacteria are introduced into the bottle, the water will have less power to fight the bacteria as time passes, which would allow the bacteria to multiply.
Whew. Does that make sense?
Anyway, I rinse my water bottle every two days.
I drank the second half of a bottle of spring water that had been sitting on my desk for over a month. It was a stupid risk to take to save about 40 cents worth of water. But I was lucky - no ill effects at all. It tasted normal.
And while I’m sure that bacteria will grow in water once the chlorine dissipates, the growth will be limited if there is nothing for the bacteria to feed on. Also, since the bottle was not exposed to air, the vast majority of bacteria in the bottle will be strains that you are already exposed to. They came from your mouth.
Getting a new bottle if you’ve been sick sounds like a good idea.