Hi there, I don't know if you can help but I'll give it a go.
I come from one of the places where people tell tourists not to drink the tap water, and to only drink from bottles as if you don't you'll contract a nasty disease on your holiday. I, coming from here, have been drinking the water out of the taps for as long as I can remember, and have never caught a disease like this so far in my life. I am planning on travelling to different countries where people also warn each other about the drinking water, but would I not carry the same risk as I have been drinking "unsuitable" water my whole life?
Thank you very much for your help!