Learn Hardcore Hausa: Ni na nema ruwa a gida amma babu. - I looked for water at home but there is none.

Na nema ruwa a gida… = I searched for water at home… (neutral).
Ni na nema ruwa a gida… = It was me who searched for water at home… (maybe not someone else).

So ni is optional and adds emphasis or contrast. Without emphasis, you’d just say Na nema ruwa a gida amma babu.

What tense or aspect is na nema?

Na nema is first person singular perfective:

na = I (subject marker in perfective).
nema = to search / to look for.

The perfective generally describes a completed action, very often translated with the simple past in English:

Na nema ruwa = I searched / I looked for water.

Compare:

Na nema ruwa – I searched (completed).
Ina nema ruwa – I am searching / I search (ongoing or habitual; progressive/imperfective).

Why doesn’t Hausa say look for with a preposition, like in English?

In Hausa, nema already includes the idea of look for / search for. You don’t need an extra preposition such as for:

English: I looked for water.
Hausa: Na nema ruwa. (literally: I searched water.)

So nema + direct object expresses look for + object. That’s normal and correct in Hausa.

Why is ruwa placed before a gida? Could we swap them?

The usual order in Hausa is:

Subject – Verb – Object – (other information like place, time, manner)

So here:

Ni / na = subject
nema = verb
ruwa = object (what you looked for)
a gida = location (where)

Hence Na nema ruwa a gida is the natural order.

Putting a gida before ruwa (e.g. Na nema a gida ruwa) would sound wrong or at least very unnatural in standard Hausa. The object normally comes before the place phrase.

What exactly does the a in a gida mean? Is it in or at?

a is a general preposition of location. It’s quite flexible and often covers both English in and at, depending on context:

a gida = in the house / at home
a kasuwa = in the market / at the market
a makaranta = in school / at school

So a gida is best understood as “at home” or “in the house” depending on how you translate the whole sentence into natural English. The Hausa preposition a does not make a sharp distinction between in and at the way English does.

What is the difference between a gida and a cikin gida?

Both are correct but slightly different in nuance:

a gida – at home / at the house (general location).
a cikin gida – inside the house (more specific: physically inside).

In many contexts they overlap, but:

Na nema ruwa a gida – I looked for water at home (could include yard, compound, etc.).
Na nema ruwa a cikin gida – I looked for water inside the house (emphasis on interior space).

Your original sentence uses the more general a gida.

What does amma mean, and where does it go in the sentence?

amma is a conjunction meaning but / however.

It functions like English but and links two clauses:

Na nema ruwa a gida amma babu.
– I looked for water at home, but there wasn’t any.

Its position is typically at the start of the second clause, just like but in English. You don’t move it around; amma goes right before the clause it introduces.

What does babu mean here? Is something missing after it?

Babu is an existential/possessive negator, roughly:

babu = there is no / there isn’t / there wasn’t / there are no / there weren’t.

In your sentence:

amma babu = but there wasn’t any (implied: water).

The word ruwa is understood from context, so you don’t have to repeat it:

Longer form: Na nema ruwa a gida amma babu ruwa.
Natural form: Na nema ruwa a gida amma babu.

This is very common in Hausa. The object after babu is often dropped if it is obvious.

Is babu a verb like “there isn’t”, or something else?

Functionally, babu acts like an existential/possessive negative:

Babu ruwa. – There is no water.
Babu kuɗi. – There is no money.
Babu littafīna. – My book is not there / I don’t have my book.

Hausa does not use a separate verb like to be here. Babu itself carries the idea of “there is not / does not exist / is not available / is not possessed”, depending on context.

So it fills the role that in English would need there is not, doesn’t have, or isn’t any.

If I want to emphasize that there was no water, can I say amma babu ruwa instead of just amma babu?

Yes. Both are correct:

Amma babu. – but there wasn’t any (water) – water is implied.
Amma babu ruwa. – but there wasn’t any water – explicit.

You might choose amma babu ruwa when:

You want to be extra clear (e.g. in early learner sentences or formal writing).
You are contrasting kinds of things:
Akwai abinci amma babu ruwa. – There was food, but there was no water.

In everyday conversation, the shorter amma babu is very natural if the missing thing (here, ruwa) has just been mentioned.

Could I say the same idea without emphasizing I, for example without ni?

Absolutely. A neutral, very common version is:

Na nema ruwa a gida amma babu.

This means the same basic thing (I looked for water at home, but there wasn’t any), without the extra emphasis on I. The version with ni:

Ni na nema ruwa a gida amma babu.

suggests a contrast or emphasis, like:

I (as opposed to someone else) looked for water at home, but there wasn’t any.

So both are grammatically fine; you choose ni na… when you want that extra focus on the subject.