hizyouyou no mizu ha omoi node, zenbu itido ni hakobukoto ha nai.

非常用 means for emergencies / emergency-use.

It is a noun-like modifier that describes what kind of water this is:

• 非常 = emergency
• 用 = use / purpose

So 非常用の水 means water for emergency use, such as stored bottled water for disasters or outages.

Here, の links two nouns.

• 非常用 = emergency-use
• 水 = water

So 非常用の水 works like emergency water or water for emergencies in English.

This is a very common Japanese pattern:

• 学校の先生 = school teacher
• 日本の文化 = Japanese culture
• 夏の服 = summer clothes

In this sentence, の shows that the water belongs to the category emergency-use.

は marks 非常用の水 as the topic of the sentence.

So the sentence is talking about as for the emergency water...

Using は gives a general or explanatory feeling:

• 非常用の水は重いので… = As for emergency water, since it’s heavy...

If you used が, it would sound more like you are specifically identifying the subject in that moment:

• 非常用の水が重いので…

That is possible in some contexts, but は is more natural when introducing the item as the topic and then making a general statement about it.

Both ので and から can mean because, but the nuance is different.

• ので sounds a bit softer, more explanatory, and often more formal or neutral.
• から can sound more direct or personal.

So:

• 重いので、全部一度に運ぶことはない。 = Since it’s heavy, there’s no need to carry it all at once.

Compared with:

• 重いから、全部一度に運ばない。 = It’s heavy, so we don’t carry it all at once.

In your sentence, ので fits the calm, explanatory tone well.

全部一度に means all of it at once.

Breakdown:

• 全部 = all / everything
• 一度に = at one time / all at once

Together they modify 運ぶ:

• 全部一度に運ぶ = to carry all of it at once

The order is natural in Japanese:

• 全部 first tells you the amount: all
• 一度に then tells you the manner/timing: at one time

Japanese often places these adverbial expressions before the verb.

In 一度に, the particle に helps turn 一度 into an adverbial expression meaning in one go / at one time / all at once.

Compare:

• 一度 = one time / once
• 一度に = at one time / all at once

So:

• 一度に食べる = eat it all at once
• 一度に覚える = memorize it all in one go
• 一度に運ぶ = carry it all at once

This is a set phrase you should learn as a chunk: 一度に.

Good question. 全部 can work in more than one way.

Here, 全部 is functioning adverbially, so 全部一度に運ぶ means carry it all at once. In this kind of usage, a particle is often omitted.

You may also see:

• 全部を一度に運ぶ

That is also grammatical, and it makes the object marking more explicit.

So:

• 全部一度に運ぶ = natural, lighter
• 全部を一度に運ぶ = also correct, a bit more explicit

Japanese often omits particles when the meaning is still clear.

こと nominalizes the verb, meaning it turns the action into a noun-like idea.

• 運ぶ = to carry
• 運ぶこと = carrying / the act of carrying

This allows the whole action to be talked about as a concept.

For example:

• 泳ぐことが好きです。 = I like swimming.
• 心配することはない。 = There is no need to worry.

In your sentence, 運ぶこと refers to the act of carrying it.

Here, 運ぶことはない is best understood as the pattern:

dictionary form + ことはない
= there is no need to ... / you don’t have to ...

So:

• 全部一度に運ぶことはない = there is no need to carry it all at once

This is a very common grammar pattern:

• 急ぐことはない。 = There’s no need to hurry.
• 心配することはない。 = There’s no need to worry.

So this sentence is not simply saying we never carry it. It is saying you do not have to carry all of it at once.

Japanese often leaves out the subject when it is understood from context.

So 運ぶことはない does not explicitly say:

• I
• we
• you
• someone

The sentence just gives a general statement or piece of advice. Depending on context, it could mean:

• you don’t need to carry it all at once
• we don’t carry it all at once
• people don’t carry it all at once

This kind of omission is extremely common in Japanese.

It sounds more like practical advice / a general recommendation.

Because of:

• 重いので = since it’s heavy
• 運ぶことはない = there’s no need to carry it

the sentence has the feeling of explaining the reason for a sensible action.

So it is not just describing a random event. It sounds like someone explaining what to do in practice: Since the emergency water is heavy, there’s no need to carry it all at once.

It is historically the topic particle は, but in this pattern it is best learned as part of the fixed expression V-ることはない.

That said, it still carries a slight contrastive nuance:

• as for doing that, there is no need

So 運ぶことはない can feel like:

• carrying it all at once is not necessary

But for learners, the most useful approach is to memorize the whole pattern:

• Verb dictionary form + ことはない
• meaning there is no need to do ...

That will help you understand many similar sentences quickly.