‘Abdallah b. ‘Umar reported the Prophet as saying, “A tenth is payable on what is watered by rain or wells, or from underground moisture, and a twentieth on what is watered by draught camels.” Bukhari transmitted it.
Hadith Referenceمشكوة المصابيح / كتاب الزكاة / 1797
Hadith Gradingالألبانی:صَحِيح | زبیر علی زئی:صحيح
Hadith Takhrij´تحقيق و تخريج: محدث العصر حافظ زبير على زئي رحمه الله` «رواه البخاري (1483)»