Сантехник сможет устранить протечку.

Сантехник is in the nominative singular. It is the subject of the sentence: the person who will do the action.

• сантехник = plumber
• nominative is the basic dictionary form for nouns when they are the subject

Because Russian marks grammatical roles with cases, the subject usually appears in the nominative.

The dictionary form is смочь, which is a perfective verb meaning to be able to, to manage to.

This can be confusing because learners often first meet мочь.

• мочь = imperfective, to be able
• смочь = perfective, to succeed in being able / to manage to

So:

• он может = he can / is able
• он сможет = he will be able

Because the sentence talks about a future situation.

• может = can / is able to now, or generally
• сможет = will be able to in the future

So Сантехник сможет устранить протечку means the plumber will be able to fix or eliminate the leak, not that he can do it right now.

After смочь or мочь, Russian normally uses an infinitive to say what someone can or will be able to do.

So the structure is:

• сможет + infinitive
• will be able to + do something

Here:

• сможет = will be able
• устранить = to eliminate / fix

Together: will be able to eliminate/fix

This is very similar to English be able to do.

Because the sentence focuses on a completed result: getting rid of the leak.

• устранить = perfective, to eliminate completely / successfully
• устранять = imperfective, to be eliminating / to eliminate in general or repeatedly

In this sentence, the idea is not the process but the successful outcome. The plumber will be able to deal with the leak completely, so устранить fits better.

Because it is the direct object of the verb устранить, so it takes the accusative case.

Протечка is a feminine noun ending in -а, and for many such nouns:

• nominative singular: -а
• accusative singular: -у

So:

• протечка = leak, in dictionary form
• устранить протечку = to eliminate/fix a leak

Yes, устранить протечку is very natural.

It means something like:

• eliminate the leak
• resolve the leak
• fix the leak

Why not починить протечку? Because починить usually means repair an object or device. A протечка is a problem or condition, so Russian often uses verbs like:

• устранить = eliminate
• ликвидировать = remove, eliminate
• исправить = correct, fix

You could say починить кран or починить трубу because those are physical things. But устранить протечку sounds especially natural because the leak is the problem being removed.

Russian has no articles like English a and the.

So протечку can mean:

• a leak
• the leak

The exact meaning depends on context. The sentence by itself does not have to specify that.

This is normal in Russian and one of the biggest differences from English.

Yes. Russian word order is more flexible than English because cases show grammatical roles.

The neutral order here is:

• Сантехник сможет устранить протечку.

This is a straightforward subject + verb + infinitive + object sentence.

But you could also change the order for emphasis, for example:

• Протечку сможет устранить сантехник.
  Emphasis on the leak or on the plumber as the one who can handle it.

Even when the order changes, the cases still help show who is doing what.

The stress is:

• сантЕхник
• смОжет
• устранИть
• протЕчку

So the full sentence is:

СантЕхник смОжет устранИть протЕчку.

A rough pronunciation guide:

san-TEKH-neek SMO-zhet oo-struh-NEET' pruh-TYECH-koo

A few notes:

• х sounds like the ch in Scottish loch or German Bach
• final ть in устранить is soft
• unstressed vowels are often reduced in normal speech, so they may sound less clear than the spelling suggests