I've gone back and forth on this a bunch of times. I eventually settled on tap, as my water supply is pretty clean and not heavily treated. Tap water can be an important source of trace minerals.
I use distilled for misting cages though, as I don't need to be scrubbing water spots off glass constantly...
I usually use tap for drinking water as well. Occasionally, I use the filtered water from the fridge is I have some left over from filling water bottles or something. But, I use the filtered water from our fridge to fill the spray bottle to mist cages as well. Water spots are a pain. LOL
Poland spring. Having once worked for a company that used ozone and reverse osmosis to treat water supplies mostly in europe. I learn unfortunately that most us states, aside from parts of california and a few others tap water isn't so great for you because of the chlorine. I fear it could affect more delicate critters easily. Just my 2 cents
I usually buy jugs of water from the store specifically for my reptiles. The dollar store usually has pretty big jugs but chain supermarket stores usually have gallon jugs for about a dollar also.
I don't know how about the tap water in foreign country, but I can make sure that in China, tap water contains much chlorine. I have 4 turtles and I never use tap water, if you really want to use tap water(it is convenient), please leave it for at least 2 days before you give it to your geckos. Whatever, I use distilled water... for bottle water, I call it dead water, because I have a friend who is selling dietary supplement, she told me that the bottle water contains nothing...no mineral substance.
Using bottled spring water for the dish and distilled for any spraying. Our well water is extremely hard even after going through multiple filters. It's what I've been using for all our other critters so doing same with our new Leo's.
I use botteled water, I only use 1 bottle every 2-3 days. If it means giving my gecko some cleaner water, Im all for it. I know they put flouride and crap in the water, which is actually classified as a poison.