This is a very literal sentence... Is this possibly an idiom of some sort in German?
I feel like no one would ever say that English sentence unless they were literally looking at some cups positioned upright in a low amount of water (or unless the cups are dense enough to sink in water, but that is getting even more strange).
For the record, I thought the translation to English would be something like "The cups have water in them".
In American English, cups generally sit. It sounds weird to have them standing. Same for glasses and mugs. But it sounds less weird when used with a drink. For example, a cup of coffee stood on the table vs. a cup of coffee sat on the table. People use the latter more often, so the first still sounds a bit odd, but not nearly as odd as "a cup stood on the table".
My apologies, I wasn't very clear at all. I'm not specifically referring to the cups in this example. I was referring to objects that are "sitting on the surface of water". Which is something we would say rather than "standing on the surface of water". I don't know where I was going with that comment, I was meant to reply to another comment. Either way, may main point was supposed to be that I agreeing that this was a silly sentence.