> This would logically imply that the standards for bottled water are <= the standards for tap water, at least in those locations.

That’s not how logic works. That there are instances of municipal water supplies whose quality is sufficient to meet bottled water standards doesn’t tell you anything about minimum standards for either municipal supplies or bottled water.

Further: I would expect quality of municipal supplies to vary widely. A city built on the side of a mountain with access to springs can just provide that water, and it’s still from “municipal” supply.

Do you have your sign reversed on that inequality? If the water comes from municipal sources, and the standards are higher for bottled water than tap (clearly stated in the link), then the quality of bottled water can be, at worst, equal to tap water.

Unless impurities are introduced at the bottling plant, or with the plastic bottles.

Municipal water has to get to your house though. How clean it is at the plant doesn't really mean much if you're in an area with bad pipes (and in many places they are).

Counties still have to do testing on the water provided by the distribution network.

Hell, in my county this information is easily available online and in libraries and is broken down by measurements in the processing plant vs measurements in the distribution network. http://www.fultoncountyga.gov/images/stories/WR2/2017/CCR_20...

This won't directly tell you if your pipes are bad (and Atlanta does have some areas that used lead pipes from the county supply to the home) but it's a pretty good indicator of the water quality in my area.

If you're really concerned, it's almost always a better investment to get your tap water tested and fix the pipes than it is to buy bottled.