"Pete C." wrote in message
You seem to loose sight of the fact that the municipal water supply
treats water so that it meets the standards for municipal water, while
the bottling plant takes that municipal water and treats it to a higher
standard for beverage production, a standard that is a good deal higher
than what your charcoal filter will produce.

Perhaps. Some municipal water is better than some bottled water from test
results I've seen. Varies, or course, but bottled water was still subjected
to the same contamination the OP was trying to avoid. It did not come from
some pure reservoir.