In the core alps (Liechtenstein, Switzerland, and Austria), you can drink water almost everywhere directly without filtering.
There are only two exceptions: If there is a thing or something like this that forbids drinking it, or if you can see an obvious reason not to drink it, like for example a strange smell or abnormal color.
In the other countries in the Alps (France, Italy, etc.)
I would only drink water unfiltered if you can drink it directly from the source, i.e. glacial lakes or the source itself.
outdoors.stackexchange.com/users/67/RoflcoptrException
If you're on an extended trip away from civilization, I wouldn't recommend it anywhere except directly from a spring coming out of rock.
If there are animals in the area, you can be sure they some have died, or done their business in the water and it could be contaminated.
While water in the alps is likely safer that rivers or lakes in most areas, I wouldn't risk it.
outdoors.stackexchange.com/users/27/Timothy Strimple
My understanding is that anything above 4000 metres you can drink due to there being a low chance that anything living will affect the water i.e. animal faeces and bacteria etc.
outdoors.stackexchange.com/users/147/Abarax
I suppose you mean outside of village, so you are talking about streams and sources.
In any alpine areas (France, Italy, Switzerland, Austria) I drink water unfiltered when I assume that there are no alps (place with cattle during summer) upstream, which worked for me.
Of course you usually cannot be 100% sure about it, but almost so.
If there is cattle upstream, you have a quite a chance of getting diarrhea.
I did it twice until now when I was just too thirsty and once came to regret that decision :)
Many people attribute diarrhea to glacier water, which I cannot confirm.
Unless you drink it constantly, the lack of minerals is not a problem either.
For dwells in towns in Switzerland you can drink always unless there is a sign telling you otherwise.
Sometimes such a sign is present as the water is not officially tested, that also very often the case in alpine huts, while the water is fine.
But you cannot know, so unless you have somebody trustful to advice you, keep away.
outdoors.stackexchange.com/users/3602/imsodin
I'm Swiss and I've been drinking water from mountain streams all my life, without any altitude restriction, while observing three basic rules.
You can drink the water if: the river is small enough to jump across it there is no cattle (alpage) above, where cows, goats and sheep may poo into the water
there is no human settlement above
Drinking this water is one of my favourite things when hiking
and I mostly go hiking carrying only a minimal amount of water to drink on the peaks where there are no rivers or sources.
I hike often (in Ticino) and managed to survive for 44 years :-)
outdoors.stackexchange.com/users/8213/Ilario
At a water faucet?
I would filter any untreated water in the Alps, and filter or boil melted snow.
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In some places,  the Swedish Lappland  for example, it's perfectly fine and even recommended to drink water directly from streams.  Is it also recommended whilst hiking in the Alps, and if so is it only in certain areas?
Where in the Alps is it safe to drink the water without filtering?
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<safety><health><water-purification><alps>
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outdoors.stackexchange.com/users/13/victoriah
Some people say that you can drink anything above 4000 metres as it is unlikely to have anything living in it that can harm you. Others say it is fin to drink from small streams providing that livestock is not kept upstream, which may be able to contaminate the water. Finally, some say that untreated water should be filtered and snow should be boiled. You can drink water above 4000 metres where there is no risk of faeces in the water. Filtering water, boiling melted snow or drinking from a faucet are also advisable.
You can drink water above 4000 metres, anywhere where there is no risk of faeces in the water. You should filter any water, boil melted snow or drink from a faucet.