Le dégât des eaux vient, par exemple, de la canalisation.

Le dégât des eaux is a very common fixed expression in French, especially in everyday life, housing, and insurance. It means water damage in the general sense.

A few useful points:

• dégât = damage
• des eaux is part of the established phrase
• French often uses this exact expression as a set term, rather than building it word-for-word from English

So even though English says water damage, French very often says dégât des eaux.

You may also see un dégât des eaux when talking about a case of water damage:

• J’ai eu un dégât des eaux. = I had water damage / I had a leak-related damage problem.

Here, des means de + les, so literally it is something like damage of the waters. That sounds odd in English, but it is normal French in this fixed expression.

Why plural?

• In many French expressions, eaux is used in a broad or general sense
• In dégât des eaux, the plural is idiomatic: it is simply the standard form of the expression

So this is not something to translate literally word for word. The best approach is to learn dégât des eaux as one chunk meaning water damage.

Yes. vient de literally means comes from, because it comes from the verb venir.

In this sentence, though, it means:

• comes from
• is caused by
• originates from

So:

• Le dégât des eaux vient de la canalisation. means that the water damage comes from / is caused by the pipework or plumbing.

This is a very natural use of venir de in French when talking about the source of a problem.

French usually needs an article before a noun in cases like this.

• canalisation is a feminine singular noun
• so the article is la
• after de, it becomes de la

So:

• de la canalisation = from the pipe / from the plumbing / from the pipework

Also, French contracts:

• de + le = du
• de + les = des

but it does not contract with la, so de la stays de la.

In this context, canalisation usually refers to:

• a pipe
• plumbing
• pipework
• a water line
• sometimes drainage or utility piping, depending on context

It does not usually mean an open canal. For a learner, plumbing pipe / pipework is often the safest idea here.

So the sentence suggests that the water damage is caused by a problem in the building’s piping system.

Par exemple means for example, and here it is inserted as a parenthetical expression.

That is why it is set off with commas:

• Le dégât des eaux vient, par exemple, de la canalisation.

It works like for example in English when you interrupt the sentence to add an illustration.

This placement is natural in French, but you could also move it:

• Par exemple, le dégât des eaux vient de la canalisation.
• Le dégât des eaux vient de la canalisation, par exemple.

The version in your sentence sounds a bit more like the speaker is inserting an example while speaking.

Not always, but very often when it is used as a parenthetical comment.

Compare:

• Le problème vient, par exemple, de la toiture.
• Par exemple, le problème vient de la toiture.

The commas depend on rhythm and style. They show that par exemple is being inserted into the sentence rather than functioning as a tightly attached phrase.

So the commas here are normal and help readability, but punctuation can vary somewhat.

Yes. Provenir de also means to come from / to originate from, and it is often a bit more formal or precise.

For example:

• Le dégât des eaux provient de la canalisation.

This is perfectly good French and may sound a little more formal than vient de.

Roughly:

• vient de = more everyday
• provient de = slightly more formal or technical

Both work in this context.

Yes, French can use both singular and plural, but the meaning can shift slightly depending on context.

• un dégât des eaux often means a case of water damage or a water-damage incident
• des dégâts means damages or damage in the countable sense

Examples:

• Il y a un dégât des eaux dans l’appartement.
  = There is water damage / a leak-related incident in the apartment.

• Le dégât des eaux a causé beaucoup de dégâts.
  = The water damage caused a lot of damage.

So in your sentence, the singular le dégât des eaux refers to the problem/event itself.

Yes, that is a very good question. Venir de has two different uses in French.

1. Literal source/origin

   • Le problème vient de la canalisation.
   • The problem comes from the pipework.

2. Recent past

   • Il vient de partir.
   • He has just left.

How do you tell the difference? By what comes after de.

• If de is followed by a noun, it usually means comes from
  • vient de la canalisation
• If de is followed by an infinitive verb, it usually means has just
  • vient de partir

So in your sentence, since de is followed by la canalisation (a noun phrase), it clearly means comes from / is caused by.

It could be understood either way depending on context, but la canalisation often refers to:

• a specific pipe already known from the situation, or
• the plumbing/pipework as the relevant system

French often uses the definite article where English might be more flexible.

So de la canalisation may mean:

• from the pipe
• from the plumbing
• from the piping system

The exact English wording depends on the situation, but the French is completely natural.