Pipa di kamar mandi itu belum diperbaiki, jadi air masih menetes.

They look the same, but they do different jobs:

• di kamar mandi: di is a preposition meaning in / at / on
• diperbaiki: di- is a passive verb prefix

A very useful spelling rule:

• If di is a preposition, it is written separately: di kamar mandi
• If di- is a prefix attached to a verb, it is written together: diperbaiki

So in this sentence:

• pipa di kamar mandi = the pipe in the bathroom
• belum diperbaiki = has not been repaired yet

Here itu can feel like either that or the, depending on context.

In Indonesian, itu after a noun often helps identify something specific:

• pipa = pipe
• pipa itu = that pipe / the pipe

In pipa di kamar mandi itu, itu refers to the specific pipe in the bathroom that both speaker and listener know about.

So although itu literally often means that, in natural English it is often best understood as simply making the noun definite, like the.

Because itu usually comes at the end of the whole noun phrase.

So:

• pipa = pipe
• pipa di kamar mandi = the pipe in the bathroom
• pipa di kamar mandi itu = that/the pipe in the bathroom

The phrase di kamar mandi is describing pipa, so the whole noun phrase is:

• [pipa] [di kamar mandi] [itu]

This is very normal Indonesian word order.
You can think of itu as attaching to the entire phrase pipa di kamar mandi.

Belum means not yet.

It suggests that something has not happened up to now, but it may happen later.

So:

• belum diperbaiki = not repaired yet

Compare:

• tidak diperbaiki = not repaired / was not repaired
• belum diperbaiki = has not been repaired yet

This is an important difference:

• tidak is plain negation
• belum adds the idea of up to now and often implies expected later

Diperbaiki is passive, and that is why the sentence focuses on the pipe, not on the person doing the repair.

• diperbaiki = be repaired
• memperbaiki = repair (active)

So:

• Pipa itu belum diperbaiki = The pipe hasn’t been repaired yet
• Seseorang belum memperbaiki pipa itu = Someone hasn’t repaired the pipe yet

Indonesian uses passive forms very naturally, often more often than English does.
If the doer is unknown, unimportant, or obvious, passive is especially common.

In this sentence, the most practical thing to know is that diperbaiki is the normal passive form meaning to be repaired.

The base is:

• baik = good
• perbaiki / memperbaiki = repair, fix
• diperbaiki = be repaired / be fixed

The ending -i is part of the verb form here. For many learners, it is easiest at first to learn memperbaiki and diperbaiki as a pair:

• memperbaiki = to repair
• diperbaiki = to be repaired

You do not need to overanalyze -i in this sentence to understand it correctly.

Here jadi means so, therefore, or as a result.

It is connecting the two clauses:

• Pipa ... belum diperbaiki = the pipe hasn’t been repaired yet
• jadi air masih menetes = so the water is still dripping

You are right that jadi can also mean become in other sentences.
But here it is being used as a connector, not a main verb.

Masih means still.

It shows that the situation continues up to the present moment.

So:

• air menetes = water drips / is dripping
• air masih menetes = the water is still dripping

This matches the earlier belum very well:

• the pipe has not been repaired yet
• so the water is still dripping

The two words work together nicely to show an ongoing problem.

Not exactly.

• menetes = to drip
• bocor = to leak

In this sentence:

• air masih menetes focuses on the water dripping
• If you said pipanya bocor, that would focus on the pipe being leaky

So the meanings are related, but not identical:

• bocor describes the leak itself
• menetes describes the action of droplets falling

Because in Indonesian, just like in English, it is natural to say water drips.

• air menetes = the water drips
• pipa bocor = the pipe leaks

So the sentence is talking first about the unrepaired pipe, and then about the result:

• the pipe hasn’t been repaired yet
• therefore the water is still dripping

That switch is completely natural.

Indonesian often does not use a separate verb equivalent to is / am / are in the way English does.

It also does not mark tense the same way English does.
Instead, it often uses context and time/aspect words such as:

• belum = not yet
• masih = still
• sudah = already

So:

• belum diperbaiki communicates something like has not been repaired yet
• masih menetes communicates something like is still dripping

English needs extra helping verbs; Indonesian often does not.

Yes, kamar mandi means bathroom.

Literally:

• kamar = room
• mandi = bathe / bathing

So it is basically bathing room.

Many common Indonesian nouns are made of two words like this.
You should learn kamar mandi as a fixed expression meaning bathroom.

It has two clauses joined by jadi:

1. Pipa di kamar mandi itu belum diperbaiki

   • Pipa di kamar mandi itu = the pipe in the bathroom
   • belum diperbaiki = has not been repaired yet

2. jadi air masih menetes

   • jadi = so / therefore
   • air = water
   • masih menetes = is still dripping

So the pattern is:

• [noun phrase] + [passive predicate], jadi [noun] + [verb phrase]

This is a very common Indonesian cause-and-result structure.