Are you sure, what you are drinking from that bottle is water. It may be a chemical stored in a water bottle. Remember when you drink water in the workplace, drink only from a sealed bottle. If that is not possible, fill water yourself from a water cooler so that you know what you are drinking is not a chemical that looks like water.
And just in case you or your colleague did drink chemical from the bottle, get help. Use the MSDS or the material safety data sheet and decide on the first aid options.