Naknada štete ne stiže, osim ako je izljev vode osigurani slučaj.

Because štete is in the genitive singular.

The basic noun is šteta = damage. After another noun like naknada (compensation), Croatian often uses the genitive to show compensation for/of something:

• naknada štete = compensation for damage
• procjena štete = assessment of damage
• uzrok štete = cause of the damage

So naknada štete is a normal noun + genitive structure.

Yes, stići literally means to arrive, but in many real contexts it can also mean to come through, to reach someone, or to be received.

So in this sentence, naknada štete ne stiže does not sound like the compensation is physically walking somewhere. It means something like:

• the compensation does not come through
• the compensation is not received
• the compensation is not paid out

This kind of wording is common in everyday and administrative language.

Croatian often uses the present tense to state general truths, conditions, policies, and rules.

So naknada štete ne stiže can mean:

• compensation is not paid
• compensation does not come
• compensation will not be paid

depending on context.

This is similar to English sentences like:

• Payment is made only if...
• Coverage applies only when...

Even though the rule may refer to future situations, the present tense is perfectly natural.

Osim ako means unless.

It introduces an exception:

• Naknada štete ne stiže, osim ako... = Damage compensation does not come / is not paid, unless...

A useful way to remember it:

• osim = except
• ako = if

So literally it is something like except if, which becomes unless in natural English.

This clause has a very normal Croatian structure:

• je = is
• izljev vode = water leakage/outflow
• osigurani slučaj = an insured event / covered event

So the clause is literally:

• unless water leakage is an insured event

Croatian word order is more flexible than English, but this order is standard and neutral in formal language.

You may also see slightly different word orders in other contexts, for example:

• osim ako izljev vode nije osigurani slučaj
• ako je izljev vode osigurani slučaj

But the version in your sentence is perfectly natural.

Because je is the 3rd person singular present of biti = to be.

The clause is an equational sentence:

• izljev vode = subject
• je = is
• osigurani slučaj = predicate noun

So it works exactly like:

• To je problem = That is a problem
• On je liječnik = He is a doctor
• Izljev vode je osigurani slučaj = Water leakage is an insured event

In the full sentence, je comes right after ako because short forms like je often appear in the second position of the clause. That is a very common Croatian pattern.

It is in the nominative singular.

That is because after biti (to be), Croatian often uses the nominative for predicate nouns:

• On je učitelj.
• To je kuća.
• Izljev vode je osigurani slučaj.

Here:

• izljev is masculine singular nominative
• osigurani slučaj is also masculine singular nominative

The adjective osigurani agrees with slučaj in gender, number, and case.

This is an insurance term. Literally, it means insured case/event, but in natural English it is usually something like:

• insured event
• covered event
• event covered by the policy

In insurance Croatian, slučaj often means a case, occurrence, or event relevant to coverage. So this is formal, industry-style language.

Because vode is in the genitive singular after the noun izljev.

This is another common noun + genitive pattern:

• čaša vode = a glass of water
• boca vina = a bottle of wine
• izljev vode = an outflow/leakage of water

So vode shows what is flowing out.

Using od vode would usually sound less natural here, because Croatian prefers the bare genitive after nouns like this.

It is definitely formal, especially because of expressions like:

• naknada štete
• izljev vode
• osigurani slučaj

This sounds like something from:

• an insurance policy
• terms and conditions
• a legal notice
• an official explanation of coverage

In casual speech, a person might say something simpler, depending on the context, but this sentence is very typical of administrative or insurance language.

Yes, depending on the tone.

Possible alternatives include:

• se ne isplaćuje = is not paid out
• ne isplaćuje se = same meaning, different word order
• ne dolazi do isplate = there is no payout
• se ne dobiva = is not received / obtained

For example:

• Naknada štete se ne isplaćuje, osim ako je izljev vode osigurani slučaj.

That version sounds even more explicitly insurance-related.
The original ne stiže is understandable and natural, but a bit less technical than se ne isplaćuje.

Yes, to some extent. Croatian word order is flexible, especially for emphasis.

For example, these are close in meaning:

• Naknada štete ne stiže, osim ako je izljev vode osigurani slučaj.
• Osim ako je izljev vode osigurani slučaj, naknada štete ne stiže.

The second version puts more focus on the condition first.

However, in formal writing, the original version sounds very natural and balanced. Not every rearrangement will sound equally good, so it is best to treat the sentence as a standard model unless you already feel comfortable with Croatian emphasis and clitic placement.