It is not permissible to make Tayammum when Water is available

Question :

I am a young student and I face difficulties with nocturnal sexual dreams; sometimes, due to the time or place, I am embarrassed and I am unable to make Ghusl immediately. So sometimes, I pray in congregation, even though I am Junub, and then I repeat it after performing Ghusl at a convenient time. And sometimes, I perform Tayammum with clean dust and then make Wudhu' after it, then I pray and I do not repeat the prayer, because of what I heard regarding the story of As-Siddiq (ie. Abu Bakr), who slept in the house of his friend and had a sexual dream, and so he performed Tayammum, because he was in doubt. Other times, I try to delay the prayer until Zuhr, so that I can perform Ghusl. What is your opinion?

Answer:

My brother, you must make Ghusl due to nocturnal emission before praying, even if you have a nocturnal emission every night, because that is an obligation of Ghusl. And since you were in the city and water was freely available, washing did not become unnecessary, and none is allowed to abandon it. Washrooms are now abundant in mosques, houses and markets and other places, therefore you must perform Ghusl in all situations, and there is no shame in matters of religion. Tayammum is only allowed when water is not available, according to Allah's Words:

...and you find no water, then perform Tayammum.

The story of As-Siddiq spending the night in the house of his friend, having a sexual dream and due to fear of doubt, making Tayammum, is not a proof. This is an exercise of Ijtihad on the part of one who made this ruling, and it is likely that it was in special circumstances, and so should not be applied in general. Therefore, there is no alternative to performing Ghusl and it is not permissible to delay it until Zuhr, when one is able to do it, nor until any other time, when one is perfectly able to perform it in full. Nor does Tayammum suffice at anytime when water is available, unless it be due to severe cold and he is unable to find some means of heating the water, and he fears death, or injury or the like will befall him if he uses the cold water; in that case, he may make Tayammum, after exhausting his abilities to do otherwise.

Source:
Ibn Jibreen
Fatawa Islamiyah, Vol. 2 Page 93