Dovodno crijevo propušta vodu.

Because crijevo is a neuter singular noun, and the adjective has to agree with it in gender, number, and case.

So:

• dovodni = masculine singular
• dovodna = feminine singular
• dovodno = neuter singular

Since crijevo is neuter, dovodno is the correct form.

Because vodu is the accusative singular form of voda.

Here, vodu is the direct object of the verb propušta. The hose is leaking or letting through water, so water is what the verb acts on.

• nominative: voda
• accusative: vodu

This is very common in Croatian:

• Pijem vodu. = I drink water.
• Vidim kuću. = I see a house.

Propušta is the 3rd person singular present tense form of the verb propuštati.

So it means:

• he/she/it lets through
• he/she/it leaks
• in this sentence, it leaks water

The subject is dovodno crijevo, which is grammatically singular, so the verb is also singular.

Not exactly in every context. Its core idea is more like to let through, to allow to pass, or to leak depending on context.

In this sentence, the natural English meaning is to leak because a hose is unintentionally letting water through.

So:

• propuštati vodu = to leak water / to let water through

In other contexts, the same verb can mean different things, depending on what is being allowed through.

Yes. Crijevo can also mean intestine/gut in other contexts.

Croatian often uses the same word for a flexible tube-like object and for an intestine. Context tells you which meaning is intended.

Here, because of dovodno and the whole sentence, it clearly means a hose or supply hose, not a body part.

A rough pronunciation guide:

• crijevo ≈ tsryeh-vo or tsree-yeh-vo
• propušta ≈ pro-POOSH-ta

A few helpful points:

• c in Croatian is always like ts in cats
• j is like English y
• š is like English sh

So:

• crijevo starts with a consonant cluster that may feel unusual to English speakers
• propušta has š, so say sh, not s

Because Croatian does not have articles like English a/an/the.

So Dovodno crijevo can mean:

• a supply hose
• the supply hose

Which one is meant depends on context. Croatian leaves that information unstated unless something else in the sentence makes it clear.

No. Croatian word order is fairly flexible because case endings show what each word is doing.

The most neutral order here is:

Dovodno crijevo propušta vodu.

But other orders are possible for emphasis, for example:

• Vodu propušta dovodno crijevo.
• Propušta vodu dovodno crijevo.

These are less neutral and would usually be used only in a particular context. For learners, the original order is the best one to use first.

Yes. That is also very natural Croatian.

Both are possible:

• pušta vodu
• propušta vodu

Very roughly:

• pušta vodu is common and everyday
• propušta vodu can sound a bit more explicit, like it is letting water through

In practical use, both can mean the hose is leaking water.

It is in the nominative singular, because it is the subject of the sentence.

You can think of it like this:

• Who/what is leaking water?
• Dovodno crijevo.

That tells you it is the subject, so nominative is the expected case.

The dictionary forms are:

• dovodan / dovodna / dovodno or more commonly listed as the adjective stem dovodni in masculine form, meaning supply / inlet
• crijevo = hose, tube, intestine
• propuštati = to let through, leak
• voda = water

When learning Croatian, verbs are normally listed in the infinitive and nouns in the nominative singular.

It normally suggests an ongoing or current situation: the hose is leaking.

That is because propušta is a present-tense imperfective form. Imperfective verbs often describe:

• ongoing actions
• repeated actions
• general situations

So this sentence sounds like a description of a problem that is happening, not a single completed event.