Sayyiduna Ali (may Allah be pleased with him) said: When a person becomes junub (in a state of major ritual impurity) in an open wilderness and he has a little water with him, he should give himself preference with the water (that is, keep it for drinking) and perform tayammum with earth.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 1107
Hadith Gradingمحدثین:صحيح لغيرهٖ
Hadith Takhrij«صحيح لغيرهٖ۔ أخرجه ابن أبي شيبة 1118»