Leviticus 15:16-18

“When a man has an emission of semen, he must bathe his entire body in water; he remains unclean until evening. Every piece of clothing and everything made of leather which gets semen on it must be washed with water; it remains unclean until evening. When a man sleeps with a woman and has an emission of semen, both are to wash in water; they remain unclean until evening.