what kind of water should i use for making coffee in coffee machines? or this can be just typical water under the tap?

Use deionized water. It is very pure with all of the impurities removed and it takes more of the flavor out of the coffee grounds so your coffee is stronger and more flavor.

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You'd better use a water filter I think. Water form tap is rarely very good...

Use onlu purified water, because the quality of coffee depends on it.

Coffee is beans and water... Water under the tap? It's better not to spend money on coffee or to chew coffee beans.

\r\n\r\nThe taste and quality of tab water is awful, so NEVER use it for any homemade food or drinks.