Numbers 19:10

19:10 The one who gathers the ashes of the heifer must wash his clothes and be ceremonially unclean until evening. This will be a permanent ordinance both for the Israelites and the resident foreigner who lives among them.

Numbers 19:17

19:17 “‘For a ceremonially unclean person you must take some of the ashes of the heifer burnt for purification from sin and pour fresh running water over them in a vessel.