Answered by Shaykh Faraz Rabbani
Does performing wudu BAREFEET in a bathroom with a toilet invalidate your wudu?
Walaikum assalam wa rahmatullahi wa barakatuh,
I pray this finds you in the best of health and spirits.
All surfaces are considered pure (tahir) until certainly established otherwise. [ Shurunbulali, Maraqi al-Falah; Ala’ al-Din Abidin, al-Hadiyya al-`Ala’iyya ] For it to be certainly established that the surface is impure, one has to either see the filth itself or its clear traces (namely, its color, smell, or taste).
As such, the floor of even a toilet is considered pure, even if it is wet. Walking on it will not render one’s feet impure–and not affect one’s wudu in any way.
This returns to the following legal principles: (1) the basis of all things is purity; (2) the basis of anything is akin to operational certainty; (3) certainty is not lifted by doubt; rather, (4) certainty is only lifted by certainty; and (5) doubts and misgivings are ignored. [ibid, and Hamwi, Hashiyat al-Ashbah; and Khadimi/Birgivi, al-Bariqa al-Mahmudiyya Sharh al-Tariqa al-Muhammadiyya]
When there is “reasonable doubt,” caution is recommended–if one isn’t giving to excessive worrying or misgivings (in which case one ignores all doubts, until such misgivings cease in one’s life).
And Allah alone gives success.
Faraz Rabbani