Numbers 19:7-8, 21

Then the priest shall wash his clothes, and he shall bathe his flesh in water, and afterward he shall come into the camp, and the priest shall be unclean until the even. And he that burneth her shall wash his clothes in water, and bathe his flesh in water, and shall be unclean until the even.

And it shall be a perpetual statute unto them: and he that sprinkleth the water for impurity shall wash his clothes, and he that toucheth the water for impurity shall be unclean until even.