Su bu iş için olmazsa olmaz.

It is a fixed Turkish expression meaning indispensable, absolutely essential, or a must-have.

It comes from the verb olmak (to be / to become / to happen) and is built like this:

• olmaz = it won’t do / it isn’t possible / it doesn’t work
• olmazsa = if it doesn’t happen / if it isn’t there
• olmaz = again, it won’t do

So the whole expression literally feels something like:

• If it’s not there, it won’t do
• or Without it, things won’t work

That literal structure helps explain why the idiomatic meaning is essential.

Because Turkish often leaves out the verb to be in the present tense, especially in 3rd person sentences like this one.

So:

• Su bu iş için olmazsa olmaz. = Water is indispensable for this job.

There is no separate word for is here.

You can make it more formal or emphatic with -dır:

• Su bu iş için olmazsa olmazdır.

That is grammatical, but in normal everyday Turkish, the shorter version without -dır is much more common.

Here, için means for.

So:

• bu iş için = for this job / for this task / for this work

A very important point for English speakers is that için comes after the noun phrase, not before it.

Compare:

• English: for this job
• Turkish: bu iş için

So için is often called a postposition, because it comes after the word or phrase it relates to.

Because için normally follows a noun phrase in its basic form.

So you say:

• iş için = for the job / for work
• bu iş için = for this job

You do not normally add the accusative ending here.

A useful detail:

• With ordinary nouns, Turkish usually uses the plain form before için.

• With personal pronouns, Turkish usually uses the genitive form:

  • benim için = for me
  • senin için = for you
  • onun için = for him/her/it

So bu iş için is exactly what you would expect.

Yes, Bu iş için su olmazsa olmaz is also natural.

Turkish word order is more flexible than English word order, and changing the order often changes the emphasis rather than the basic meaning.

• Su bu iş için olmazsa olmaz. This makes su the topic: we are talking about water, and saying that for this job it is essential.

• Bu iş için su olmazsa olmaz. This can put stronger attention on su as the crucial thing for the job.

In both versions, the main meaning stays the same.

Yes, definitely.

• önemli = important
• gerekli = necessary
• olmazsa olmaz = absolutely essential / indispensable / something you cannot do without

So olmazsa olmaz is stronger and more emphatic.

If you say:

• Su bu iş için gerekli. you mean Water is necessary for this job.

But:

• Su bu iş için olmazsa olmaz. means more like Water is absolutely essential for this job.

In this sentence, it works as the predicate of the sentence, like a predicate adjective or predicate noun in English.

So in:

• Su bu iş için olmazsa olmaz.

olmazsa olmaz describes su by saying what it is: an indispensable thing for this job.

This expression is flexible in Turkish. It can behave a bit like:

• an adjective: olmazsa olmaz bir unsur = an indispensable element
• or a noun-like expression: Bu işin olmazsa olmazı sudur = Water is the indispensable element of this job

So learners will often see it used in both ways.

By itself, it could theoretically be either:

• su = water
• Su = a female given name

Because this word is at the start of the sentence, it is capitalized anyway, so capitalization does not help us.

In this sentence, context normally tells us it means water:

• Su bu iş için olmazsa olmaz. = Water is indispensable for this job.

If Su were a person’s name, the sentence would mean:

• Su is indispensable for this job.

So the grammar is the same; only the context decides.

It is very natural and very common.

Olmazsa olmaz is a fixed expression that native speakers use a lot in:

• everyday conversation
• advertising
• workplace language
• social media
• general writing

It is slightly idiomatic, because its literal pieces do not match English very neatly, but it is absolutely standard Turkish.

So this is a useful phrase to learn as a whole chunk:

• X olmazsa olmaz = X is indispensable / X is a must

Yes — that is a very useful pattern.

A common structure is:

• X, Y için olmazsa olmaz. = X is indispensable for Y.

For example:

• Sabır bu iş için olmazsa olmaz. = Patience is indispensable for this job.
• Deneyim bu meslek için olmazsa olmaz. = Experience is indispensable for this profession.
• Güven bir ilişki için olmazsa olmaz. = Trust is indispensable for a relationship.

So the sentence you have is a very good model you can reuse.