It's very common on Santorini to drink bottled water. We didn't have any problem with ice, fruits, etc.
Is it safe to put ice in Greece?
If they are made with tap water, they may not be safe to consume, especially in the Greek Islands. However, many hotels use bottled water to make ice cubes, which gets you a safe drink. If you have any doubts, we recommend removing the ice cubes from your drink before they have a chance to melt.