Can I get sick from drinking old water?!
Other than a plastic taste, no harm done. The actual water we drink has been around for eons before it is pumped out of the ground. And though a bottle has an expiration date, it does not spoil. An open container may be a catch-all for dust, bugs, and anything else in the air which would take away some appeal. So under normal circumstances, water that's contained is safe to drink.
No. All water is old water. You only get sick from contaminated water.
No, you will only get sick if the water contains organism that would give rise to illness. Don't be paranoid...
Nope. Water can begin to taste a little funny after sitting out, but it won't affect your health.
water doesn't have an expiration date, you will be fine