Sicily drinking water?

Trapani was having an issue with their water being infiltrated with sea water a few years ago, and drinking tap water was not recommended. No idea if that is still the case. Not an issue elsewhere as far as I know.

Ortigia had salty water when we were there in April 2023.
As we stayed in apartments everywhere, I just boiled a jug full and kept it in the fridge.
In Ortigia we had to buy bottled water.

Basically the water is safe, meets standards, just may not taste the best due to salt or chlorine.

Most people I saw drink filtered/bottled water.

It's safe. In many locations the local water district has free or very cheap fountains (like 10 cents for a liter), including carbonated one. It's generally purified with reverse ozone osmosis, therefore it doesn't taste like chlorine.

However bottled water from the grocery store is so cheap in Italy, that you don't need to fret if you don't see a public fountain nearby.

At the grocery store in Tuscany I pay on average no more than 50-75 cents per 1.5liter bottle (they come in a pack of 6) and some brands are under 25 cents per liter. Even a pack with 6 small 0.5L bottles, won't cost you more than 25 cents each. Coffee shops in tourist areas might sell it for a bit more, but nothing like we pay in the US.

I religiously use a steel bottle at home, but I feel less bad about buying bottles in Italy because recycling at least appears to be taken seriously--everywhere I have stayed on the last two trips required separation of all waste.

Ice will be ok but you might prefer to use bottled water. Best is to ask your host where you are staying. In some places in Sicily water provision can sometimes be lacking so houses have a reserve tank on the roof, fine for cooking, but best to drink bottled if you're not sure.

Thank you, appreciate all the advice, I really don't want to add to one time plastic bottle issue, fountains and large bottled water would help.