Breakdown of Er zit wat in het filter.
in
in
er
there (existential)
zitten
to be (located) in
wat
something / some (a little)
Questions & Answers about Er zit wat in het filter.
Why use wat here instead of iets?
In conversational Dutch, wat is very often used as a shorter, unstressed alternative to iets (something). There is no difference in meaning between Er zit wat in het filter and Er zit iets in het filter, but wat sounds a bit more casual and flows very naturally in spoken language.
How can I tell that wat means "something" here and not "a little"?
When wat means "a little" or "some", it is usually followed by an uncountable noun or an adjective, like in wat suiker (a little sugar) or wat leuks (something nice). Here, it stands completely on its own as the subject of the sentence, which tells you it means "something".
Why does the sentence use zit (sits) instead of is (is)?
Dutch strongly prefers positional verbs (zitten, staan, liggen) over zijn (to be) to describe where things are located. Because the mystery object is trapped or contained inside an enclosed space (the filter), zitten is the most natural choice. You use er zit to mean "there is (located inside)".
Wait, is filter a het-word? I thought I had seen de filter.