At my in laws house I noticed someone’s slippers were not too dissimilar to a pair of slippers my wife used to have, which were made from pig leather.
I seen the slippers were wet and gathered that the person had made wudhu in them and was praying Salah in the same carpeted room as my wife, who had performed wudhu in alternative footwear.
My wife must have therefore walked in the same areas.

In the name of Allah, the most Beneficent, the most Merciful.

Answer

Firstly, not all slippers and sandals are made from pig leather; therefore, you should not fall into any unnecessary doubts and waswasas.

There is a principle in Islamic jurisprudence which is:

“Certainty is not lifted by a doubt.” (Al Ashbah Wan Nadhair p.60)

If something is pure apparently, then having a doubt that it is impure would not lift the certainty of it being pure.

However, if the slippers were made from pig leather then when the slippers became wet the impurity would have passed on to the carpet, hence, if there are visible traces of the impurity on the carpet that area will be considered impure. To make that area pure one should pour water over it three times. (Nurul Idah p.54)

Only Allah Knows Best

Mohammed Tosir Miah

Darul Ifta Birmingham