The Messenger of Allah ﷺ said: No one of you should make water in his bath and then wash himself there (after urination). The version of Ahmad has: Then performs ablution there, for evil thoughts come from it.  

قَالَ رَسُولُ اللَّهِ ﷺ لاَ يَبُولَنَّ أَحَدُكُمْ فِي مُسْتَحَمِّهِ ثُمَّ يَغْتَسِلُ فِيهِ قَالَ أَحْمَدُ ثُمَّ يَتَوَضَّأُ فِيهِ فَإِنَّ عَامَّةَ الْوَسْوَاسِ مِنْهُ  

Humayd al-Himyari said: I met a man (Companion of the Prophet) who remained in the company of the Prophet ﷺ just as AbuHurayrah remained in his company. He then added: The Messenger of Allah ﷺ forbade that anyone amongst us should comb (his hair) every day or urinate in the place where he takes a bath.  

لَقِيتُ رَجُلاً صَحِبَ النَّبِيَّ ﷺ كَمَا صَحِبَهُ أَبُو هُرَيْرَةَ قَالَ نَهَى رَسُولُ اللَّهِ ﷺ أَنْ يَمْتَشِطَ أَحَدُنَا كُلَّ يَوْمٍ أَوْ يَبُولَ فِي مُغْتَسَلِهِ