The Messenger of Allah forbade urinating into standing water.
Sunan Ibn Majah Book 1, Hadith 77
← Previous Hadith The Messenger of Allah said: "No two people should converse while relieving themselves, each of them looking at the private parts of the other, for Allah, the Mighty and Sublime, hates that." (Da'if)

Other chains with similar wording.

Sunan Ibn Majah Book 1, Hadith 76 Next Hadith → "The Messenger of Allah said: 'No one among you should urinate into standing water.'"

Sunan Ibn Majah Book 1, Hadith 78