Not necessarily, all bottled water may not be filtered and/or treated and therefore an expiration date may be just that an expiration date. Water, for long-term storage should be purified/treated/filtered, not only to remove organisms, but various chemicals. Bottled water quality can and will often vary considerable from bottler to bottler and even lot to lot. The source of the water will have a lot to do with what chemical and organic materials may be dissolved in the water. Mineral or spring water will by their very nature may have substantial minerals (chemicals) and organics dissolved in the water. These minerals can interfere with the chemical disinfection process of the water, if that is the method the bottler uses for disinfection.

Water, one might purchase from a supermarket where they have a self-serve bottle filler, is likely nothing more then water from the city/town’s municipal water source that travels though a pre-filter, charcoal bed filter and may finally pass through a UV treatment device (for bacterial/viral/fungal). In fact a lot of bottled water is nothing more then municipal water that is passed through a device described above, but on a commercial grade level.

With that all said it is still probably okay to drink water from a sealed water bottle well beyond said expiration date. It is still likely equal to or better then water from a questionable water source. One could always boil or treat/filter the bottled water if in any doubt.

Pete