The World Federation One Stop Fiqh

Ruling 295

If on some parts of the body on which wuḍūʾ is performed there is an obstruction which water sometimes manages to go under by itself and at other times it does not, and if one doubts after performing wuḍūʾ whether water went under it or not, then, in the event that he knows that while he was performing wuḍūʾ he was not aware of water going under it, the recommended precaution is that he should perform wuḍūʾ again.