El agua parece pura.

Because agua is still feminine, but Spanish uses the masculine-looking singular article el before many feminine nouns that begin with a stressed a- or ha- sound.

So:

• el agua
• el águila
• el hacha

This is done mainly for ease of pronunciation: la agua sounds awkward.

But the noun is still feminine, which you can see in other words that agree with it:

• el agua pura
• mucha agua
• esta agua

In the plural, the normal feminine article returns:

• las aguas

Because adjective agreement follows the gender of the noun, not the form of the article.

Even though the article is el, the noun agua is still feminine, so the adjective must also be feminine:

• el agua pura
• not el agua puro

This is one of the most important things to remember with nouns like agua:
the article may look masculine, but the noun is feminine.

Parecer means to seem or to appear, so parece pura means seems pure.

There is a difference:

• El agua parece pura = The water seems pure.
  
  • This expresses an impression, not certainty.
• El agua es pura = The water is pure.
  
  • This sounds like a statement of fact.
• El agua está pura is generally not the natural choice here.
  
  • Estar is not normally used with puro in this meaning.

So if the idea is it looks pure / it appears to be pure, then parece pura is the right choice.

Because parecer already works like a linking verb here.

In English, we say:

• The water seems pure

Not:

• The water seems to be pure unless we want a slightly fuller structure.

Spanish does the same thing:

• El agua parece pura

Here, parece directly connects the subject (el agua) with the adjective (pura). No extra ser is needed.

You can also say:

• El agua parece ser pura

But that is more formal or heavier in style. The shorter version is more natural in everyday Spanish.

Parece is the third-person singular present tense of parecer.

The infinitive is:

• parecer = to seem / to appear

Present tense:

• yo parezco
• tú pareces
• él / ella / usted parece
• nosotros/as parecemos
• vosotros/as parecéis
• ellos / ellas / ustedes parecen

In El agua parece pura, the subject is el agua, which is singular, so we use parece.

It is singular.

Even though water can be an uncountable noun in English, in Spanish agua is grammatically a singular noun in this sentence:

• el agua = the water

That is why the verb is singular:

• parece, not parecen

If it were plural, you would have something like:

• Las aguas parecen puras = The waters seem pure

But that is a different meaning and is less common in everyday use.

In Spanish, a noun like agua usually needs an article when you are talking about a specific instance or about it in a general, natural way.

So:

• El agua parece pura sounds normal.
• Agua parece pura sounds incomplete or unnatural in most contexts.

Spanish uses articles more often than English does. English can sometimes say Water seems pure, but Spanish often prefers El agua parece pura.

In Spain, agua is pronounced roughly like AH-gwa.

A few details:

• a = an open a sound
• gua = gwa
• The g in agua is a normal hard g, because it comes before u

So the word has two syllables:

• a-gua

The stress is on the first syllable:

• Água

That stressed initial a is exactly why Spanish uses el instead of la before it in the singular.

The normal, neutral word order is:

• El agua parece pura

That is the most natural way to say it.

Spanish word order is more flexible than English, so other orders are sometimes possible, but they usually add emphasis or sound literary, poetic, or unusual:

• Pura parece el agua = sounds marked or stylistic, as if emphasizing pura
• Parece pura el agua = generally awkward in ordinary speech

For a learner, the safest and most natural version is:

• El agua parece pura

Yes, depending on context.

In this sentence, parece pura can often be translated naturally as:

• seems pure
• looks pure
• appears pure

But the core meaning is it gives the impression of being pure.

So parecer is a useful verb when you do not want to fully state something as a fact.

Usually, you would say:

• Esta agua parece pura

not Este agua parece pura.

Even though agua takes el in the singular, it is still feminine, so demonstratives stay feminine:

• esta agua
• esa agua
• aquella agua

This is a very common point of confusion.

So compare:

• el agua
• esta agua
• mucha agua
• agua pura

All of those show that agua is grammatically feminine.

In the plural, the special use of el disappears, and the regular feminine plural article is used:

• las aguas

So:

• el agua pura = the pure water
• las aguas puras = the pure waters

Notice that everything clearly shows feminine agreement in the plural:

• las
• puras

This helps confirm that agua is feminine even in the singular.

Normally, in this kind of sentence, pura appears after the verb because it is functioning as an adjective linked to the noun by parece:

• El agua parece pura

If you use the adjective directly with the noun, the most neutral order is also after the noun:

• el agua pura

Putting pura before the noun is possible in some contexts, but it often changes the tone or emphasis and may sound literary or less literal.

For learners, the standard pattern is:

• noun + adjective
• el agua pura

and with parecer:

• El agua parece pura