LXX Num 19:10

καὶ πλυνεῖ τὰ ἱμάτια ὁ συνάγων τὴν σποδιὰν τῆς δαμάλεως, καὶ ἀκάθαρτος ἔσται ἕως ἑσπέρας· καὶ ἔσται τοῖς υἱοῖς Ἰσραὴλ καὶ τοῖς προσκειμένοις προσηλύτοις νόμιμον αἰώνιον.

The man who has gathered up the ashes of the heifer must also wash his clothes, and he will be ceremonially unclean until evening. This is a permanent statute for the Israelites and for the foreigner residing among them.