Question about my Boas humidifier?

I have BRB, we've had him for about 1 month or so. We also have a humidifier. The BRB is my brothers, but he goes a boarding school ... so basically it's mine. Anyways my brother told me to never put tap water into the humidifier and I always listened, but my dad has been getting pissed that we wait the water bottles. So instead I bought a jug .. and I've realized it keeps filling up, and now I looked at the bottle on the humidifier and it has little bubbles in it and turns out it's tap water and my dad has attempted to trick us ... will tap water harm the snake & the humidifier or was my brother lying?