Nước đọng ở trên sàn nhà.

Đọng means something like to collect, to remain still, or to pool.

So nước đọng is standing water, pooled water, or water that has collected and is not flowing away.

In this sentence, đọng is describing the state of the water.

Vietnamese often does not use a verb like to be in places where English does.

So instead of saying:

• Water is pooled on the floor

Vietnamese can simply say:

• Nước đọng ở trên sàn nhà

Literally, it is more like:

• Water pooled / collecting on the floor

This is very normal in Vietnamese. You do not need là here.

Vietnamese commonly puts the thing being talked about first.

Here, nước is the topic/subject: the sentence is about the water.

Structure-wise, this is roughly:

• Nước = water
• đọng = is pooled / has collected
• ở trên sàn nhà = on the floor

So the order is very natural:
thing + state/action + location

Both can refer to location, but they work a little differently.

• trên = on, above
• ở trên = at/on/above, with ở making the location relationship more explicit

In this sentence, ở trên sàn nhà means on the floor.

You will often hear both:

• Nước đọng trên sàn nhà.
• Nước đọng ở trên sàn nhà.

Both are understandable and natural.
The version with ở can feel a bit more explicit about location.

Sàn nhà specifically means the floor of a house or room.

• sàn can mean a floor, platform, deck, stage surface, etc.
• sàn nhà makes it clear that we mean the indoor floor

So sàn nhà is often the more specific and natural choice when talking about water on a room floor.

Yes, nhà by itself often means house or home, but in sàn nhà, it forms a compound meaning house floor or simply floor.

So here, you should understand sàn nhà as one unit:

• sàn nhà = floor

This is very common in Vietnamese: words combine to create a more specific meaning.

Yes, it is natural.

Some other natural ways to say something similar are:

• Có nước đọng trên sàn nhà. = There is standing water on the floor.
• Nước đọng trên sàn nhà.
• Sàn nhà có nước đọng. = The floor has standing water on it.

The original sentence is fine. It sounds like a neutral description of the situation.

The difference is mostly in focus:

• Nước đọng ở trên sàn nhà focuses on the water and where it is.
• Có nước đọng trên sàn nhà means there is standing water on the floor, which is more like introducing the existence of it.

So:

• Nước đọng... = talking about the water
• Có nước đọng... = saying that such water exists there

Both are common.

Usually nước đọng suggests water that has collected, so it is stronger than just saying the floor is damp or wet.

It often implies:

• a puddle
• pooled water
• water that has not drained away

If you only want to say the floor is wet, you might say something like:

• Sàn nhà bị ướt. = The floor is wet.

So nước đọng usually points to visible collected water, not just moisture.

Yes. Đọng can be used more broadly for things that remain, accumulate, or stay behind.

For example, depending on context, it can refer to:

• liquid collecting
• something lingering
• residue or impression remaining

But with nước, the meaning is very straightforward: water has pooled/collected.

Vietnamese does not use articles in the same way English does.

So:

• nước can mean water, the water, or sometimes some water
• sàn nhà can mean the floor or a floor, depending on context

The context tells you how specific it is.

That is why Nước đọng ở trên sàn nhà can be translated naturally as Water is pooled on the floor or There is standing water on the floor, even though there is no direct word for the.

Very roughly, yes, if you break it apart word by word:

• ở = at / located at
• trên = on / above
• sàn nhà = floor

But you should not translate it too mechanically.
As a whole, ở trên sàn nhà simply means on the floor.

Vietnamese often combines a location marker like ở with a position word like trên, dưới, trong, etc.

A rough pronunciation guide is:

• Nước — something like nook with a short clipped ending
• đọng — roughly dawng with a heavy falling tone
• ở — like uh with a rising, questioning-like tone
• trên — roughly chane or train without the final English n
• sàn — roughly sahn with a low falling tone
• nhà — roughly nyah with a low falling tone

A more important point than the English approximation is that each syllable has its own tone, and those tones matter a lot in Vietnamese.

Yes, you could, but it changes the nuance a little.

• Nước đọng ở trên sàn nhà = The water is pooled on the floor.
• Nước đang đọng ở trên sàn nhà = The water is currently collecting/pooling on the floor.

Adding đang emphasizes an ongoing process.
Without đang, the sentence simply describes the state more neutrally.

It is mainly describing a state.

Even though đọng can feel verb-like, in this sentence it is really telling you the condition of the water: it has collected and is sitting there.

So the sentence is not mainly about the water doing something active. It is about the water being in a pooled state on the floor.