Bottled water is sold with an expiration date on the label, but that doesn't necessarily mean you can't still drink it once the date has passed. This video explains how water can potentially become undrinkable, and when it's safe to drink otherwise.
If you've ever left a glass of water out overnight and taken a sip the next day, you probably noticed that it tasted a little funky. You might suspect that the water started to spoil, but this video from the DNews YouTube Channel explains that the funky taste is actually because the water was exposed to air, making it slightly more acidic and potentially filled with things like dust and microbes. It's probably still safe to drink for another day or so as long as it wasn't outside, but it will continue to get more gross over time.
Bottle water, however, keeps dust, oxygen, and microbes at bay. That means, according to the CDC, bottled water can be safe to consume for a very long time as long as it's stored out of direct sunlight (or high heat), kept away from pesticides and gasoline, and the bottle isn't compromised.
Essentially, you can ignore the expiration dates on your bottled water; just make sure it was stored safely (and that you're getting enough every day).
Does Water Ever Expire? [YouTube]