L’infiltration vient de la canalisation.

Because French usually elides le or la before a word that begins with a vowel or a silent h.

• la infiltration becomes l’infiltration
• This is similar to:
  • l’eau instead of la eau
  • l’école instead of la école

So L’infiltration is just the normal shortened form of la infiltration.

Here, vient de means comes from.

So:

• L’infiltration vient de la canalisation. = The seepage/leak is coming from the pipe/plumbing.

Be careful: venir de + infinitive can also mean has just done something:

• Je viens de manger = I have just eaten

But that is a different structure. In your sentence, de la canalisation is a noun phrase, so vient de means comes from.

Because canalisation is a feminine noun.

• masculine: du = de + le
• feminine: de la

So:

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

Compare:

• le tuyau → du tuyau
• la canalisation → de la canalisation

Canalisation often means a pipe, piping, water line, or more generally part of the plumbing system.

Depending on context, it may be translated as:

• pipe
• plumbing
• water line
• drain line
• pipeline

It is a bit broader than just one physical pipe. In home-repair contexts, French often uses canalisation where English might say pipe or plumbing.

Because the subject is L’infiltration, which is singular.

• l’infiltration = singular
• so the verb is vient (singular form of venir)

Compare:

• L’infiltration vient de la canalisation.
• Les infiltrations viennent de la canalisation.

Also, the verb agrees with the subject in number, not in gender. Even though infiltration is feminine, that does not change the verb form.

Not exactly.

In French, infiltration often refers to water seeping in, water ingress, or penetration of water into a wall, ceiling, floor, etc.

A direct leak from a pipe is often:

• une fuite

So in some contexts:

• une fuite = a leak
• une infiltration = seepage / water infiltration

That said, in practical translation, English might still use leak depending on the situation.

Yes, possibly — but it changes the nuance.

• La fuite vient de la canalisation = The leak comes from the pipe/plumbing
• L’infiltration vient de la canalisation = The seepage/water ingress comes from the pipe/plumbing

Use fuite when you are talking about the actual leak itself. Use infiltration when you are talking about water entering somewhere it should not, often through a wall, ceiling, or structure.

A simple pronunciation guide is:

L’infiltration vient de la canalisation
lan-feel-tra-see-on vee-an de la ka-na-lee-za-see-on

A few useful points:

• vient has a nasal vowel; the final t is silent.
• infiltration and canalisation both end in -tion, pronounced roughly like see-on in French.
• de is usually pronounced lightly, almost like duh.

A more IPA-style pronunciation is roughly:

/lɛ̃.fil.tʁa.sjɔ̃ vjɛ̃ də la ka.na.li.za.sjɔ̃/

Yes. Provient de also means comes from or originates from, and it can sound a bit more formal or precise.

• L’infiltration vient de la canalisation.
• L’infiltration provient de la canalisation.

Both are correct.
In everyday speech, vient de is very common and natural.

Because de only contracts with le and les, not with la.

So:

• de + le = du
• de + les = des
• de + la = de la
• de + l’ = de l’

That is why you get:

• de la canalisation not
• du canalisation

Yes, it is natural, especially in a maintenance, plumbing, or building-damage context.

It sounds like something someone might say when identifying the source of water damage:

• L’infiltration vient de la canalisation. = the water seepage is caused by the pipe/plumbing.

Depending on context, French speakers might also say:

• L’infiltration est due à la canalisation.
• Le problème vient de la canalisation.
• Il y a une fuite dans la canalisation.

But your original sentence is perfectly normal.