Language:
كتاب الوضوء
4
Ablutions (Wudu')
(68)
Chapter: Urinating in stagnant water
(68)
باب الْبَوْلِ فِي الْمَاءِ الدَّائِمِ

The same narrator said that the Prophet (ﷺ) had said:

"You should not pass urine in stagnant water which is not flowing then (you may need to) wash in it."

وَبِإِسْنَادِهِ قَالَ ‏ "‏ لاَ يَبُولَنَّ أَحَدُكُمْ فِي الْمَاءِ الدَّائِمِ الَّذِي لاَ يَجْرِي، ثُمَّ يَغْتَسِلُ فِيهِ ‏"‏‏.‏
Reference : Sahih al-Bukhari 239
In-book reference : Book 4, Hadith 106
USC-MSA web (English) reference : Vol. 1, Book 4, Hadith 240
  (deprecated numbering scheme)