Numbers 19:7-8, 21

“Then the priest must wash his clothes and bathe himself in water. Afterward he may return to the camp, though he will remain ceremonially unclean until evening. The man who burns the animal must also wash his clothes and bathe himself in water, and he, too, will remain unclean until evening.

This is a permanent law for the people. Those who sprinkle the water of purification must afterward wash their clothes, and anyone who then touches the water used for purification will remain defiled until evening.