L'aigua és allà.

Because Catalan usually shortens el or la to l' before a word that begins with a vowel (or silent h).

So:

• la + aigua → l'aigua

This is called elision. It makes the phrase easier to pronounce.

Yes. Aigua is a feminine noun.

You can see that from the article:

• la aigua → l'aigua

And you can also see it when an adjective agrees with it:

• l'aigua freda = the cold water

So even though you only see l', the underlying article is la, not el.

Catalan uses the definite article more often than English.

In a sentence like L'aigua és allà, the article often suggests that the speaker means specific water already known from the context: the water.

Also, Catalan often uses the article with nouns in places where English might not. Compare:

• L'aigua és important. = Water is important.

So l'aigua can sometimes correspond to English the water, and sometimes just water, depending on context.

És is the third-person singular form of ser, meaning is.

So:

• és = is

The accent is important because és is a different word from es.

• és = is
• es = a pronoun used in reflexive/passive-type constructions

So the accent helps you identify the correct word.

This is a very common question.

In Catalan, ser is often used for simple location, especially in standard/basic usage:

• On és el llibre? = Where is the book?
• És a la taula. = It is on the table.

So L'aigua és allà is a normal way to say that the water is there.

Estar is also used in Catalan, but more often for states/conditions, and in some varieties it can also be used for location in certain contexts. For a beginner, though, és allà is a very good standard model.

Allà means there or over there.

It usually refers to a place away from the speaker. In many contexts, it can feel a bit like over there in English.

Catalan also has allí, which can also mean there. In some dialects, allà and allí are very close in meaning, while regional preferences may differ. For this sentence, just learn:

• allà = there / over there

Because L'aigua és allà and Hi ha aigua allà do not mean the same thing.

• L'aigua és allà = the water is there
  
  • You are talking about the location of something specific.
• Hi ha aigua allà = there is water there
  
  • You are saying that water exists / is present in that place.

So ser + location word and hi ha are used for different kinds of statements.

A rough pronunciation guide is:

• l'aigua ≈ LYE-gwa or EYE-gwa, depending on how carefully you break it up and on dialect
• és ≈ ess
• allà ≈ ah-LYA

A few notes:

• In aigua, the ai sounds like English eye.
• In allà, the ll is a Catalan sound often approximated by ly.
• The accent in allà shows that the stress is on the last syllable: al-LÀ.

Pronunciation varies by dialect, but this will get you close.

Yes, if the context already makes it clear what you are talking about.

Catalan often leaves out information that is understood from context. So:

• És allà. = It is there.

But if you want to explicitly say the water, then L'aigua és allà is the full version.

No. English often needs a subject pronoun, but Catalan does not use an extra pronoun here because the subject is already present:

• L'aigua = the subject
• és = is
• allà = there

So L'aigua és allà is complete as it stands. There is no need to add a separate word for it.