Is it permissible to perform ghusl from janabah by filling a basin with water while keeping the tap running?

If a person in a state of ritual impurity (junub) bathes in a basin containing water, and the water is two qullahs or more (approximately 200 liters), the bathing is valid by consensus, though it is disliked by the Shafi'is. However, if the water is less than two qullahs, there is a difference of opinion among scholars:

Imam Shafi'i and those who agreed with him held that the bathing is valid and removes the state of ritual impurity, though it is disliked.

Others held that the bathing is not valid, and that the water becomes musta'mal (used water) and does not remove the ritual impurity, citing the Prophet's (peace be upon him) prohibition: "None of you should bathe in standing water while he is in a state of ritual impurity (junub)."

The most cautious and preferred approach is to avoid bathing in stagnant water, whether it is little or abundant.