The ruling on tayammum when water is present and the time when it is permissible

Question:
He says: I have seen some people performing tayammum while water is available. Do they have a valid prayer? And when is tayammum permissible according to the Shari'ah?

Answer:
If a Muslim finds water, he has no right to perform tayammum, neither in settled areas nor in the desert, neither while traveling nor while resident, neither in the desert nor in the city. He must perform wudu' with water and perform ghusl with water from janabah. The same applies to a woman regarding menstruation and post-natal bleeding. Tayammum is only permissible for him when water is absent, or when he is unable to use it due to illness, sores, or the like, as Allah (Glorified and Exalted is He) said: : [Surat al-Nisa: 43]. Therefore, the believer only performs tayammum when water is absent, or when he is unable to use it due to illnesses, wounds, or sores that prevent the use of water. He has no right to perform tayammum while water is present. Those who perform tayammum while water is available and have no ailment, their prayer is not valid. They must be informed that this is a reprehensible act, it is not permissible, and their prayer is not valid.
However, if they have an ailment, illnesses that prevent the use of water, meaning: and the doctors have confirmed that it prevents the use of water, then they are excused, and praise be to Allah. Yes.