"Potrzebuję trochę wody."

Translation: I need some water.

[MiriRubin0]

Why is water in genitive rather than accusative here?

[Jellei]

Words describing quantity, like "trochę", take Genitive.

[Wippii]

Is it because expressions of quantity often mean "[quantity] of something"?

Also, I thought the genitive here was because of potrzebować.
Once again the comment section proves useful, so thank you. :D

[Jellei]

Hmm... because of both, I guess :D

[kat747761]

Alem, you are lovely with your Polish language. Good job :)

[DotairRaib]

When would you use "jakaś" to mean "some" in comparison to the examples already given? And what case would "woda" take after "jakaś"?

[alik1989]

Jakaś works like an adjective, so it doesn't dictate the case, it inflects.

Potrzebuję jakiejś (genitive) wody (genitive).

But that means "I need some kind of water", indicating that the object is countable. It might work in a context where you stand in front of a store shelf with bottled water and have to pick a bottle. But it's not a translation of 'I need some water'.

[akikotsukamoto]

if potrzebuje takes genitive, when troche should be also genitive?

[Jellei]

"trochę" is a numeral, it doesn't undergo declension through cases, there are no other forms.

"trochę" itself takes Genitive as well.

[FinnHasson]

Would "wody" without "troche" (sorry, I can't do the accent on my keyboard) be sufficient to communicate the idea of "some"? I may be confusing it with Russian, but I thought genitive could also be used partitively to communicate the idea of "some."

[Arnoldpitt]

Some doew not express the idea of a small amount I believe troche means. A drop or a little would be better

[Jellei]

I think it works well, "trochę" is just some unspecified amount, true, probably small, but still. "a little" works. "a drop", even though I understand that's not literally a single drop, sounds rather like a very small amount...