Urinating in stagnant water Sahih al-Bukhari 239
Arabic hadith text
وَبِإِسْنَادِهِ قَالَ "لاَ يَبُولَنَّ أَحَدُكُمْ فِي الْمَاءِ الدَّائِمِ الَّذِي لاَ يَجْرِي، ثُمَّ يَغْتَسِلُ فِيهِ "
Translation
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."