The water pours out from a tap. The water pours out from the tap.

The water pours from the tap. the sentence is a little short it's is a "snippet" with no context to work on "the water is pouring from the tap" "the water is pouring out of the tap" This​ would be for a situation if the tap was broken or not turned off correctly or had a very bad leak

I could just tell you that you should say "The water pours out from a tap", but I see this as a good opportunity to notice a pattern that could be helpful later on: There are three main parts to this sentence: [The water] [pours] [out from a tap] 1. A Noun Phrase subject "The water" 2. A Verb "pours" tells us about an event. 3. A Prepositional Phrase "out from a tap" made up from a Preposition "out" and its complement phrase "from a tap". The Prepositional Phrase tells us more information about how the event happened - the water could have poured "slowly", "earlier", or "suddenly", but instead we're talking about its source, in this case, "a tap" The sentence you gave was almost correct, but the Preposition "out" was separated from its complement "from a tap". If you move it too far away from those words, then the reader/listener can't tell that "out" is supposed to be related to them. It would be better to say "The water pours out from a tap" because now the Preposition comes directly in front of the source "from a tap" So that's the general rule - Prepositions come directly before their complement words. And you can use it all the time!: The man fell [OUT of the plane] The clock hangs [FROM the wall] in the kitchen I sat [WITH my friends] for an hour I know that was a bit wordy, but hopefully its something that can help later!

As a general statement I would tend to say: Water pours out from a tap To speak about a specific tap I'd say: Water pours out from the tap To refer more directly to the water I'd say: The water pours out from the tap

It depends on context, but it can be: "the water goes out of the tap".