Answered by Shaykh Faraz Rabbani
If pure water falls on the floor of the bathroom, and my clothes drag on this and soak it up do I have to change my clothes?
Walaikum assalam wa rahmatullah,
I pray this finds you in the best of health and spirits.
The default assumption about bathroom and toilet floors–like all things–is purity. This is our operational certainty, and the legal maxim is that, “Certainty is not lifted by mere doubts.” [Ibn Nujaym, al-Ashbah wa’l Nadha’ir] Thus, if your clothes drag on the bathroom floor, you would assume that the wetness isn’t filthy. This is supported by rigorously authentic hadiths of the Messenger of Allah (peace and blessings be upon him), narrated by Imam Tirmidhi and others.
And Allah alone gives success.
Faraz Rabbani