In other words, it is tap water. You can't even count on waters that are labeled 'purified' to be sterile enough for mixing baby formula. The enforcement of bottled water guidelines is minimal. There is no overall assurance that bottled water is safer to drink than tap water. On a national level bottled water is not as regulated as tap water.
Most testing is done by the bottler only.
There's no national testing for Cryptosporidium cyst in bottled water. There is no requirement for putting expiration dates on bottled water. Stored bottled water can be a breeding ground for bacteria. Pierre Payment, a Canadian researcher, found bacteria counts in bottled water even higher than in tap water. Storing water in soft plastic containers can increase the potential for a higher concentration of leached contaminants.