I do think a lot of water can be trusted. But we do use our own water filters and UV filtration system no matter where we go just to be safe. We do know there are places in Mexico where the water is fine. We also know there are places in the US where the water is not OK. To be safe we do our own filtering and UV purification (1 gallon per minute UV costs about $100 plus installation). I mentioned some websites earlier in this thread. Based on test results by experts we do not trust bottled water. We have read NY City tap water is the best water you can drink. Who knew?