Sayyiduna Abdullah bin Mughaffal (may Allah be pleased with him) said that the Messenger of Allah (peace and blessings be upon him) said: "None of you should urinate in his bathing place and then bathe or perform ablution in it, for most of the whisperings (waswasah) come from it."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 473