Ruling 665 - 6. Performing wuḍūʾ or ghusl conflicts with another legal responsibility that is more important or just as important

If someone has a little water and his body or clothing is impure, and were he to perform wuḍūʾ or ghusl with that water there would not be enough left over with which he could wash his body or clothing, he must wash his body or clothing with the water and perform prayers with tayammum. However, if one does not have anything with which he can perform tayammum, he must use the water for wuḍūʾ or ghusl and perform prayers with his impure body or clothing.