Leviticus 15:16-18

“If a man has an emission of semen, he shall bathe his whole body in water and be unclean until the evening. And every garment and every skin on which the semen comes shall be washed with water and be unclean until the evening. If a man lies with a woman and has an emission of semen, both of them shall bathe themselves in water and be unclean until the evening.