The Messenger of Allah ﷺ said, "Do not urinate in still water that does not flow and then bathe in it."
وقال رسول الله ﷺ لا تبل في الماء الدائم الذي لا يجري ثم تغتسل منه
This is a sahih hadith, and it is in the Individual Manuscript, number 73. Muslim narrated it [1:162-163 S / 1:93 Bulaq] through its transmission line, but Bukhari did not narrate it through that line. However, he narrated it with the same meaning at [1:298-299 Fath], from a different hadith, through the transmission line of the Aaraj recension. Its meaning has already occurred through other routes from Abu Hurairah, numbers 7517, 7518, 7592, 7855.As for his saying, "Do not urinate in standing water," this is what is established in the original copies of the Musnad and in Jami al-Masanid, and it agrees with Muslim's narration through the transmission line of the Manuscript. In the Individual Manuscript it reads, "Urination should not be done in standing water." What is in the Musnad and in Muslim is more reliable and more sahih.