Sunan an-Nasa'i
Book 1: The Book of Purification
كتاب الطهارة
325 hadith in this book
Chapter 25 Squatting While Urinating In The House
باب الْبَوْلِ فِي الْبَيْتِ جَالِسًا
It was narrated that 'Aishah said: "Whoever tells you that the Messenger of Allah (ﷺ) urinated standing up, do not believe him, for he would not urinate except while squatting."
أَخْبَرَنَا عَلِيُّ بْنُ حُجْرٍ، قَالَ أَنْبَأَنَا شَرِيكٌ، عَنِ الْمِقْدَامِ بْنِ شُرَيْحٍ، عَنْ أَبِيهِ، عَنْ عَائِشَةَ، قَالَتْ مَنْ حَدَّثَكُمْ أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم بَالَ قَائِمًا فَلاَ تُصَدِّقُوهُ مَا كَانَ يَبُولُ إِلاَّ جَالِسًا .
Hadith text, translations and grading are courtesy of Sunnah.com.