El enjuague usa agua fría.

Because enjuague is a masculine noun, so it takes el in the singular.

Spanish nouns do not always show their gender clearly from the ending. Even though enjuague ends in -e, it is masculine, so you learn it as el enjuague.

Depending on context, enjuague can mean things like:

• rinse
• rinsing
• rinse cycle
• sometimes mouthwash

Usa is the third-person singular present tense of usar.

That form can mean:

• he uses
• she uses
• it uses
• you use in the usted form

In this sentence, the subject is el enjuague, so usa means uses in the sense of it uses.

The subject is el enjuague.

A simple way to see it:

• El enjuague = the subject
• usa = the verb
• agua fría = what is being used

So the structure is basically: The rinse uses cold water.

Spanish often leaves out the article with a noun when speaking about something in a general or material/substance sense.

So usa agua fría means it uses cold water in general, not a specific batch of water.

Compare:

• usa agua fría = it uses cold water
• usa el agua fría = it uses the cold water

The second version sounds more specific.

Agua is feminine.

That can be confusing because when it has a singular definite article, you usually say el agua, not la agua. This happens because feminine nouns that begin with a stressed a- sound often use el in the singular for easier pronunciation.

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

• el agua fría
• mucha agua
• las aguas frías

So in your sentence, fría is feminine because agua is feminine.

Because fría describes agua, and agua is feminine.

Adjectives in Spanish usually agree with the noun they describe in gender and number:

• agua fría = cold water
• vino frío = cold wine

Even if agua sometimes appears with el, it is still feminine, so the adjective stays feminine: fría.

Because in Spanish, descriptive adjectives usually come after the noun.

So:

• agua fría = cold water
• casa grande = big house
• libro interesante = interesting book

Putting the adjective after the noun is the normal pattern here.

The accent mark shows that fría is pronounced with two syllables in that part: frí-a.

Without the accent, Spanish pronunciation rules would push it toward a different rhythm. The written accent helps show the correct stress and vowel separation.

So it is pronounced roughly: FREE-ah

Enjuague is pronounced roughly like:

en-HWA-ge

A few helpful details:

• j in Latin American Spanish sounds like a strong English h, but rougher
• the u in the final gue is not pronounced
• the stress falls on jua: en-JUA-gue

So the whole word sounds approximately like: en-HWA-geh

Yes. Utiliza is also correct.

Both mean basically the same thing, but:

• usa sounds more everyday and direct
• utiliza sounds a little more formal or technical

So El enjuague usa agua fría is natural and simple.

Yes. Enjuague is a context-dependent word.

For example, it could refer to:

• the rinse step in washing
• a rinse cycle
• the act of rinsing
• sometimes a rinse product, such as mouthwash in some contexts

So the exact English translation depends on what kind of process or product the sentence is talking about.