My lo's face breaks out whenever i give her a bath. thinking that it's the faucet water's fault, i tried purified water. and it worked. what gives?!?

Many Possibilities!: Humans are complex living creatures, embodied souls, if you will. Something/several things in faucet water might be relevant, but so may temperature, how the water is used & under what associated conditions/situations applied. Keep in mind that water, after birth, includes the threat of drowning/suffocation, issues which could engender intense, non-verbal reactions & lo's hx drives her responses.