No, actually, the water bottling companies use those dates just like the food processing companies do. It's a means of rotating stock. It's not required by law. And if the consumer determines that past-date means no longer safe to consume, so it gets tossed and replaced, so much the better. All that date means is that the company guarantees that the water will still taste good up through that date.
In general, as long as the integrity of the bottle isn't compromised, the water is still safe to drink. Even if there are algae growing in the bottle, most algae are harmless. If your bottled water is suspect, it can be boiled or passed through a water filter before consuming it.
However, it is important to keep in mind that water is an extremely effective, if slow-acting, solvent. Chemicals will eventually leach from plastic bottles into the water over time. Sunlight and heat accelerate the leaching process, and this will gradually affect the taste of the water.
Some wonder about the safety of drinking water from bottles that have been subjected to temperature extremes. Plastic water bottles are designed to withstand freezing without leaking or becoming otherwise compromised. Water that has been frozen in new commercial water bottles is perfectly safe to consume.
The real concern is with bottles exposed to extreme heat. One of the most popular places to store emergency water is actually in the back of a car. A hot car can reach temperatures of over 150 degrees Fahrenheit in the summer. Laboratory experiments have shown that it takes 38 days for water from water bottles heated to this temperature to contain antimony levels in excess of safe levels as determined by the government.
Bottled water should be stored just like foods--away from light, heat, and chemical fumes.
Now, have you ever given a thought to bottling your own water? Commercially bottled water is not necessarily free of contaminants. It just meets federal safety standards. In fact, most bottled water is just tap water from the municipality where it was bottled. You might actually have cleaner water coming out of your own faucet.
Refilling soda and juice bottles is commonly practiced by many who wish to store water for emergencies. Simply refill bottles, add bleach if desired, screw on the lid, and store.
However, you can also bottle your own water that will last indefinitely and without adding bleach. Glass juice bottles are a natural for this. The metal caps have a sealing compound just like canning lids and if they haven't been tweaked, they will reseal on glass jars. Simply refill the glass bottles, apply the lid, and process in a boiling water bath for ten minutes.
You can also do the same thing with canning jars. It's not my favorite way to store water or use canning jars, because I want them for food. However, it is an option, especially if you aren't using them anyway. You can reuse lids that aren't tweaked--there is no great loss if they don't seal. This is a good option for having clean, safe water on hand for baby formula or other needs, without the risk of leached chemicals from plastic.
Links to related posts:
Comparison of Water Purification Methods
Best-By Dates--What Those Numbers Really Mean
For further information:
https://www.nsf.org/newsroom/bottled-water-tips
06.04.20
