Al-Kāfi - Volume 3 > One’s having Little Water on a Journey but Is Afraid of Facing Thirst
Hadith #3

3ـ عَلِيُّ بْنُ إِبْرَاهِيمَ عَنْ أَبِيهِ عَنِ ابْنِ أَبِي عُمَيْرٍ عَنْ مُحَمَّدِ بْنِ حُمْرَانَ وَجَمِيلٍ قَالاَ قُلْنَا لأَبِي عَبْدِ الله (عَلَيْهِ الْسَّلام) إِمَامُ قَوْمٍ أَصَابَتْهُ جَنَابَةٌ فِي السَّفَرِ وَلَيْسَ مَعَهُ مَاءٌ يَكْفِيهِ لِلْغُسْلِ أَ يَتَوَضَّأُ بَعْضُهُمْ وَيُصَلِّي بِهِمْ قَالَ لاَ وَلَكِنْ يَتَيَمَّمُ وَيُصَلِّي بِهِمْ فَإِنَّ الله عَزَّ وَجَلَّ قَدْ جَعَلَ التُّرَابَ طَهُوراً.

3. Ali ibn Ibrahim has narrated from his father from ibn abu ‘Umayr from Muhammad ibn Humran and Jamil who have said the following: “Once we asked abu ‘Abd Allah, ‘Alayhi al-Salam, about the case of the Imam of a people during a journey who experiences sexual relation and does not have enough water for Ghusl (bath). Can another person from among them take Wudu’ and lead them in Salah (prayer)? He (the Imam) said, ‘No, they cannot do so; however, he must take Tayammum and lead them in Salah (prayer); Allah, most Majestic, most Glorious, has made the soil purifying.’”