I have been in a hotels in Thailand where I was either told or there was a sign telling the guest, that they had two bottles of water a day, free. If more than two bottles were opened, there was a charge added to the bill. At one hotel, they charged me for a bottle and claimed that the seal was broken. I did not open it, but paid for it. I was charged 20 or 40 baht for the water. At 7/11 the same size cost 10 baht or less.
To resolve that issue in the hotels that charge for more than two bottles and I am staying more than 2 or 3 days, I do what my Thai wife does, buy 2 liter bottles of water from a near by store. That way I have enough water for my coffee, that I make in my room.
Those were not cheap hotels either. Except the one that a Thai friend of the family reserved for me. I only stayed one night there. After that experience, I told friends, I would make my own reservations.
What was odd at one hotel was, even though I bought my own water, every day there were two more free bottles in the room!