Is building a swimming pool in one's personal villa considered unlawful (haram), especially if it is for the purpose of learning to swim, taking into account the suspicion of extravagance (tabdhir) in water usage?

Allah condemned the squanderers, saying: "Indeed, the squanderers are brothers of the devils." Prodigality is spending on what is unlawful. Ibn Mas'ud, Ibn Abbas, Mujahid, and Qatadah said: Prodigality is spending money on disobedience to Allah or on what is unlawful. Al-Shafi'i and the majority of scholars said: Prodigality is spending money on what is unlawful, and there is no prodigality in doing good deeds. Based on this, there is no harm in building a swimming pool in a villa if it serves a legitimate purpose.