Sunan Ibn Majah, Chapter: The Chapters of Purification and its Sunnah

"The Messenger of Allah (saw) said: 'None of you should urinate in his wash area for most of the insinuating thoughts* come from that." (Daif) Abu Abdullah bin Majah said: ("Abul-Hasan said: 'I heard Muhammad (SAW) bin Yazid** saying:) "Ali bin Muhammad (SAW) At-Tanafisi said: 'This (prohibition) applies to cases where the ground (in the place used for washing) was soft. But nowadays this does not apply, because the baths you use now are built of plaster, Saruj*** and tar; so if a person urinates there then pours water over it, that clears it away, and that is fine.'" *i.e., doubts about whether the urine has touched him and made him impure. **That is Ibn Majah, being a statement from one of the manuscripts. ***A mixture of chalk and sand.