Si la cisterna no se arregla hoy, llamaré otra vez a la fontanera.

In this sentence, la cisterna most naturally means the toilet cistern / toilet tank in a bathroom.

In Spain, that is a very common meaning, especially because the sentence also mentions la fontanera (the plumber). So the idea is that something is wrong with the toilet’s water tank or flushing mechanism.

Fontanera means female plumber in Spain.

• el fontanero = male plumber
• la fontanera = female plumber

The feminine ending -a shows that the plumber is a woman. In English, plumber does not change form, but in Spanish many job names do.

Also, la shows it is a specific plumber, not just any plumber.

Here se arregla means gets fixed or is fixed.

Spanish often uses se when the important thing is the result, not who does the action. So:

• Si la cisterna no se arregla hoy... = If the cistern doesn’t get fixed today...

This is very natural in Spanish.

If you wanted to mention people more directly, you could also say:

• Si no arreglan la cisterna hoy... = If they don’t fix the cistern today...

Both are possible, but se arregla sounds very natural when the agent is unknown or unimportant.

Because Spanish normally uses this pattern for a real future condition:

• si + present indicative, then
• future in the main clause

So:

• Si la cisterna no se arregla hoy, llamaré...

This is the normal structure for if X happens, I will Y.

English does something very similar:

• If it doesn’t get fixed today, I’ll call again

Notice that English also uses the present after if, not will.

Normally, no.

In standard Spanish, after si for a real future condition, you do not use the future tense. So:

• ✅ Si la cisterna no se arregla hoy, llamaré...
• ❌ Si la cisterna no se arreglará hoy, llamaré...

That second version sounds wrong in normal modern usage.

Yes, you could.

• llamaré = I will call
• voy a llamar = I’m going to call

Both are natural in Spain.

The version with llamaré is a little more compact and slightly more neutral or written in tone.
The version with voy a llamar can sound a bit more immediate or conversational.

So both work:

• Si la cisterna no se arregla hoy, llamaré otra vez a la fontanera
• Si la cisterna no se arregla hoy, voy a llamar otra vez a la fontanera

Because llamar is used with a before the person you call:

• llamar a alguien = to call someone

So:

• llamar a la fontanera
• llamar a Marta
• llamar al médico

This a is required here. It is part of how the verb works.

Otra vez means again or one more time.

So:

• llamaré otra vez = I’ll call again

Yes, de nuevo is very similar:

• Llamaré de nuevo a la fontanera

Both are correct. In everyday speech, otra vez is extremely common.

Depending on tone, otra vez can sometimes sound slightly like again, yet again, but in this sentence it just means again.

Yes. That is another very natural way to say I’ll call again.

• Llamaré otra vez a la fontanera
• Volveré a llamar a la fontanera

Both are correct and common.

Volver a + infinitive is a very useful structure in Spanish:

• Volví a intentarlo = I tried again
• Volveré a escribirle = I’ll write to him/her again

Yes. You can put the si clause first or second.

Both are natural:

• Si la cisterna no se arregla hoy, llamaré otra vez a la fontanera
• Llamaré otra vez a la fontanera si la cisterna no se arregla hoy

The meaning stays the same. The difference is mostly one of emphasis and rhythm.

Because the si clause comes first.

In Spanish, when a conditional clause comes before the main clause, it is normally separated by a comma:

• Si la cisterna no se arregla hoy, llamaré otra vez a la fontanera

If you reverse the order, you normally do not use a comma:

• Llamaré otra vez a la fontanera si la cisterna no se arregla hoy

Because si meaning if never has an accent.

Compare:

• si = if
• sí = yes

So in this sentence, it must be si, because it introduces a condition.

More or less, yes.

Both can mean to fix / to repair:

• arreglar
• reparar

But arreglar is often a bit more everyday and common in conversation. Reparar can sound a bit more technical or formal.

So these are both possible:

• Si la cisterna no se arregla hoy...
• Si la cisterna no se repara hoy...

In everyday Spanish in Spain, arreglar sounds very natural here.