Assuming from the tap, the general answer is no – don’t do that. The water isn’t chemically stripped of bacteria like it is in most western countries.
So you should only drink mineral water from bottles, just try not to use single use plastic bottles and fill up your own water bottle instead from your hotel/hostel/villa. Every accommodation has a water filter or giant water bottle dispenser because you cannot drink the tap water – so make use of it!
You can wash cutlery and pots and pans in the tap water, just make sure it’s dry first before using it again. If it isn’t, get some mineral water and give it a mini wash/wipe down with that water before using.
You can use tap water to brush your teeth, just minimise swallowing of the water. Initially I would recommend using mineral water to brush and gargle. Then slowly use tap water to brush your teeth and only gargle with mineral water. Then eventually you should be fine, like I am, to brush teeth, tongue and gargle with the tap water!
If you ever drink the tap water accidentally then just have a glass of mineral water, that should dilute it a bit!
If you get a drink of water from a restaurant, they usually will always serve you mineral water. Most places give you a glass for free upon arrival, or you can order a fancier mineral water too.
If you get ice cubes in your drink, they should be shaped like a curved cylinder shape with a hole right through the middle that you could fit a straw through. This is ice cubes bought that made with mineral water and are safe to have in your drink. If they don’t look like this, consider tossing it.