Leviticus 15:19
17 and he must wash in water any clothing or leather that has semen on it, and it will be unclean until evening. 18 As for a woman whom a man goes to bed with, then has a seminal emission, they must bathe in water and be unclean until evening. 19 “‘When a woman has a discharge and her discharge is blood from her body, she is to be in her menstruation seven days, and anyone who touches her will be unclean until evening. 20 Anything she lies on during her menstruation will be unclean, and anything she sits on will be unclean. 21 Anyone who touches her bed must wash his clothes, bathe in water, and be unclean until evening.
2 Samuel 11:4
2 One evening David got up from his bed and walked around on the roof of his palace. From the roof he saw a woman bathing. Now this woman was very attractive. 3 So David sent someone to inquire about the woman. The messenger said, “Isn’t this Bathsheba, the daughter of Eliam, the wife of Uriah the Hittite?” 4 David sent some messengers to get her. She came to him and he went to bed with her. (Now at that time she was in the process of purifying herself from her menstrual uncleanness.) Then she returned to her home. 5 The woman conceived and then sent word to David saying, “I’m pregnant.” 6 So David sent a message to Joab that said, “Send me Uriah the Hittite.” So Joab sent Uriah to David.
Notes and References
"... The assumption is that because the laws of impurity constitute a meaningful system, the rules for each type of impurity have implications for the other types. For example, for the parturient the consequences of impurity are spelled out: she is not to have contact with consecrated things or to enter the sanctuary (Leviticus 12:4). These consequences are not mentioned for the other types of impurity in the Torah, but with other readers, ancient and modem, I assume that they apply to them as well. But the applicability of rules for one type of impurity to other types is not always clear. Leviticus 15 decrees laundering and bathing for the man with a flow at the end of the period of purification (Leviticus 15:13) and bathing for a man who has had a seminal emission and for a woman who has had contact with semen in sexual relations (Leviticus 15:16, 18). Yet it mentions neither bathing nor laundering for the menstruant or the woman with abnormal flow. Still P surely assumes such bathing and laundering. Its failure to specify them may reflect its confidence that the analogy with the man with a flow and the man with a seminal emission would be obvious, and there is evidence elsewhere in the Bible, outside of P, for the practice of bathing after menstruation (2 Samuel 11:4). But if the silence of Leviticus 15 is due to its already having laid out the rules in the first portion of the chapter, why does its discussion of the woman with an abnormal flow repeat the requirement of sacrifice (Leviticus 15:29–30) in language virtually identical to that it uses for the man with a flow (Leviticus 15:14–15)? The assumption that P’s laws form a system by no means explains all aspects of their literary expression ..."
Himmelfarb, Martha Between Temple and Torah: Essays on Priests, Scribes, and Visionaries in the Second Temple Period and Beyond (p. 140) Mohr Siebeck, 2013