Сантехник спас квартиру от протечки.

Because сантехник is the subject of the sentence, so it stays in the nominative case.

• сантехник = plumber
• It is a masculine singular noun
• In the past tense, the verb form also matches this masculine singular subject: спас

So the basic structure is:

Сантехник + спас + квартиру + от протечки
The plumber + saved + the apartment + from a leak

Спас is the past tense masculine singular form of спасти, which is a perfective verb.

That tells you:

• the action happened in the past
• it is seen as completed
• the subject is masculine singular

Compare:

• Он спас = he saved
• Она спасла = she saved
• Они спасли = they saved

Since сантехник is masculine singular, спас is the correct form.

This is an aspect question.

• спас = perfective
  Focuses on the result: the apartment was successfully saved.
• спасал = imperfective
  Focuses on the process, repeated action, or an attempt.

So:

• Сантехник спас квартиру от протечки.
  The plumber managed to save the apartment from the leak.
• Сантехник спасал квартиру от протечки.
  The plumber was trying to save / was in the process of saving the apartment from the leak.

In your sentence, the perfective verb makes sense because the speaker is talking about a successful completed event.

Because квартиру is the direct object of the verb спас.

The verb спасти / спасать usually takes:

• кого? что? = the thing/person being saved

Here, what did the plumber save?

• квартиру = the apartment

Since квартира is a feminine noun ending in -а, its accusative singular form is:

• квартира → квартиру

So:

• nominative: квартира
• accusative: квартиру

Yes—this is normal Russian usage.

Russian often uses спасти что-то от чего-то not only for people, but also for places, objects, and property:

• спасти дом от пожара = save the house from a fire
• спасти урожай от заморозков = save the crop from frost
• спасти квартиру от протечки = save the apartment from a leak

In natural English, depending on context, you might also say:

• prevent the apartment from being damaged by a leak
• save the apartment from water damage
• protect the apartment from a leak

But the Russian wording itself is completely natural.

After the preposition от, Russian here uses the genitive case.

So:

• протечка = leak
• от протечки = from a leak

The pattern is:

• спасти кого? что? от кого? от чего?
• save someone/something from someone/something

That is why:

• протечка → протечки
  genitive singular

Протечка means a leak, especially a leak causing water to come through where it should not.

It often refers to things like:

• a leaking roof
• leaking pipes
• water seeping through the ceiling
• a plumbing leak

It is a very common word in housing and repair contexts.

Related words:

• течь = leak, leakage
• протекать = to leak
• утечка = leak in some contexts too, but often used for things like gas, data, information, etc.

So in this sentence, протечка strongly suggests a household water leak.

Because Russian has no articles.

Russian does not have direct equivalents of English a/an and the. Whether something is definite or indefinite is understood from:

• context
• word order
• emphasis
• general situation

So Сантехник спас квартиру от протечки could correspond to English as:

• The plumber saved the apartment from the leak
• A plumber saved an apartment from a leak

In real context, the listener usually already knows which plumber or which apartment is meant.

Yes. Russian word order is much more flexible than English word order.

The neutral order here is:

Сантехник спас квартиру от протечки.

But you could also say:

• Квартиру от протечки спас сантехник.
• От протечки квартиру спас сантехник.

These alternatives change the focus or emphasis, not the basic meaning.

For example:

• Сантехник спас квартиру от протечки.
  Neutral: tells what happened.
• Квартиру от протечки спас сантехник.
  Emphasizes that it was the apartment that got saved, and the plumber was the one who did it.
• От протечки квартиру спас сантехник.
  Emphasizes the danger/source: from the leak.

Not necessarily in real life—but grammatically, yes, the form is masculine.

Russian past tense verbs agree with the subject in:

• gender in the singular
• number

So:

• сантехник спас = masculine singular
• сантехник спасла would be grammatically wrong, because сантехник is a masculine noun
• сантехники спасли = plural

Even if the actual person were female, Russian would normally use a different noun, such as сантехница in some contexts, though in real usage many job titles are still commonly said in the masculine.

Usually сантехник means a plumber or a worker dealing with plumbing/sanitary systems.

It can include things like:

• pipes
• water supply
• drains
• toilets
• radiators
• leaks

So in this sentence, сантехник is exactly the kind of person you would expect to deal with протечка.

Yes, depending on the exact situation.

For example:

• от затопления = from flooding
• от потопа = from a flood/deluge
• от течи = from a leak

The choice changes the nuance:

• протечка = the leak itself
• затопление = the flooding or water damage result
• течь = leakage, a leak, often a bit more technical or concise
• потоп = a major flood, sometimes dramatic or colloquial

So от протечки is a natural and straightforward choice if the problem is specifically a leak.

The stress is:

• сантЕхник
• спАс
• квартИру
• от протЕчки

A rough pronunciation guide:

• сантЕхник ≈ san-TEKH-neek
• спАс ≈ spahs
• квартИру ≈ kvar-TEE-roo
• протЕчки ≈ pra-TYECH-kee

Stress matters in Russian, so it is worth learning words together with their stressed syllable.