Hi @Julie143 .
I agree with both @Sarah977 & @Marie21 .
I have safe water, and offer the same as you, plus a bottle of water per person. I also see it as a safety issue.
If I was to supply environmentally friendly empty bottles, to decant and fill as they tour around, there would be questions of hygiene and more likely, they would “walk” with them to their next tourist site and stay.
As my climate is very hot and dehydration a reality, giving a bottle allows them to refill and take in the car. It costs me about 80cents Australian to do this per person. I consider this cost in my daily rate.
I’ve had guests who don’t use them as they travel responsibly with their own bottle/vessel for filling, or even if the water is safe, they go and buy copious water from the shops.
We can’t change a persons habits, just inform why we do or do not provide bottled water.