الجسم محتاج ميه.

A common pronunciation is:

el-gism meḥtāg mayya

A few notes:

• الـ is usually pronounced el- in Egyptian Arabic.
• ج in Egyptian Arabic is usually a hard g sound, so الجسم sounds like el-gism, not el-jism.
• ح in محتاج is a strong breathy ḥ sound, deeper than normal English h.
• ميه is commonly pronounced mayya. You may also hear slight variation depending on speaker.

Because Arabic often leaves out is / am / are in the present tense.

So:

• الجسم = the body
• محتاج = needing / in need of
• ميه = water

Literally, the structure is something like:

The body needing water

But in natural English, that means:

The body needs water
or
The body is in need of water

This is completely normal in Arabic.

محتاج means needing, in need of, or it needs depending on context.

It comes from a word pattern that often works like an adjective or active participle. In everyday Egyptian Arabic, محتاج is very common and useful.

Examples:

• أنا محتاج مساعدة = I need help
• إنت محتاج راحة = You need rest
• الجسم محتاج ميه = The body needs water

So even though it is not a verb in the same way as English need, it often translates that way.

الجسم means the body, while جسم means a body or just body.

In Arabic, using the definite article often sounds natural when talking about something in a general sense, especially something understood in context.

So الجسم محتاج ميه can mean:

• The body needs water
• or more generally, The body needs water as a fact about the human body

If you said جسم محتاج ميه, it would sound more like a body needs water or a body is needing water, which is less natural in this kind of statement.

Because ميه is the everyday Egyptian Arabic word for water.

• ميه / مية = colloquial Egyptian Arabic
• ماء = Modern Standard Arabic or more formal Arabic

So:

• الجسم محتاج ميه sounds natural in Egyptian speech.
• الجسم يحتاج إلى الماء would sound formal and more like written Standard Arabic.

If you are learning Egyptian Arabic for conversation, ميه is the form you want.

Actually, it does agree, and it already matches.

• الجسم is grammatically masculine singular
• محتاج here is also masculine singular

That is why محتاج is the correct form.

If the subject changed, the form would also change. For example:

• البنت محتاجة ميه = The girl needs water
• البنات محتاجين ميه = The girls need water
  or in some speech, محتاجات may appear in more careful/formal styles, but محتاجين is very common colloquially

So in your sentence, محتاج matches الجسم correctly.

In Egyptian Arabic, محتاج is often followed directly by the thing needed.

So:

• محتاج ميه = needs water
• محتاج فلوس = needs money
• محتاج وقت = needs time

In more formal Arabic, you may learn structures like:

• يحتاج إلى الماء = he/it needs water

But in Egyptian Arabic, the direct pattern without a preposition is very common and natural.

The structure is:

الجسم + محتاج + ميه
subject + predicate + thing needed

More specifically:

• الجسم = the topic/subject
• محتاج = describes the subject
• ميه = what is needed

So the logic is:

The body — in need of — water

This kind of structure is very common in Arabic.

Yes, you could, and it would be understandable and natural in Egyptian Arabic.

Compare the two:

• الجسم محتاج ميه = The body needs water
• الجسم عايز ميه = literally The body wants water, but often used like needs in everyday speech

The difference is mostly nuance:

• محتاج sounds a bit more like needs / is in need of
• عايز is very common in conversation and can mean wanting or sometimes needing, depending on context

For a health or body-related statement, محتاج often sounds especially appropriate.

Yes. In Egyptian Arabic writing, you may see both:

• ميه
• مية

Both represent the colloquial word water.

Because colloquial Arabic spelling is less standardized than formal Arabic, variation like this is normal. A learner should recognize both.

It is colloquial Egyptian Arabic.

Clues:

• ميه instead of formal ماء
• محتاج used in a very conversational Egyptian way
• the overall sentence feels spoken and natural, not formal or literary

A more formal Modern Standard Arabic version would be something like:

الجسم يحتاج إلى الماء

That is not how most Egyptians would normally say it in casual speech.

You would usually say:

جسمي محتاج ميه

That breaks down as:

• جسم = body
• ـي = my

So جسمي = my body

Then:

• جسمي محتاج ميه = My body needs water

This is very useful because Arabic often adds pronouns directly onto nouns like this.

In this sentence, it clearly means the physical body.

But جسم can also mean:

• body in the physical sense
• sometimes object or mass/body in scientific contexts

Here, because of محتاج ميه, the meaning is definitely the human or living body needing water.

So a learner should understand it as:

the body in the health/physical sense.