It is haram for the person who is junub (in a state of impurity following sexual activity) to perform salah (ritual Prayer), perform Tawaf, stay in the mosque, recite or touch the Qur’an. Everything else is permissible.
However, there is nothing wrong with a person who is junub to cook, look after the house, take care of the children, or fulfill any other needs.
Sheikh M. S. Al-Munajjid, a prominent Saudi Muslim lecturer and author, states: “There is no set time limit within which a woman who is junub has to do ghusl (purificatory bath). It has to do with the performance of Prayers and other acts of worship where taharah (purity) is required. There is no harm in delaying ghusl until the time for the next Prayer comes. But it is recommended for the Muslim to hasten to do ghusl so that he or she will always be in a state of taharah, as is the sunnah, and because the angels do not come near a person who is junub. The Prophet (peace and blessings be upon him) said: “There are three things which the angels do not approach: the dead body of a kafir, a man who has perfumed himself with saffron [because this is frivolous and foolish behavior and an imitation of women (Fayd Al-Qadeer, 3/325)], and a person who is junub until he does ghusl” (Reported by Abu Dawud).
If a woman is busy and it is not easy for her to do ghusl from janabah (impurity) straight after intercourse, this does not affect her and she is not najis (impure). It is sufficient for her to do wudu’ (ablution), to reduce the janabah and so that the angels will come near her.
The claim that some people make, that it is haram for a woman who is junub to touch things and to do certain things, is all innovated (bid`ah) and false ideas which have no basis in Islam. This false belief is based on false and fabricated hadiths that have been reported on this topic. Sheikh Ash-Shuqairi (may Allah have mercy on him) said: Among these false ideas is the notion that if a woman who is junub kneads dough, it becomes corrupt because of her janabah, and that the barakah (blessing) will vanish from everything her hand touches. (As-Sunan wal-Mubtada`at, p. 31).
The Standing Committee on Scientific Research and Fatwas stated that: it is permissible for a person—whether a man or a woman—who is junub to touch things such as clothes, plates, pots, and so on before doing ghusl because this person is not najis and does not make the things he or she touches najis. It was reported in an authentic hadith that Abu Hurayrah (may Allah be pleased with him) was with the Prophet (peace and blessings be upon him) one day; then he withdrew from him, then he came back. The Prophet (peace and blessings be upon him) said to him: “Where were you, Abu Hurayrah?” He said, “I was junub and I did not want to sit with you when I was not tahir (pure).” The Prophet (peace and blessings be upon him) said, “Subhan Allah, a Muslim does not become najis” (Reported by Al-Bukhari).
And Allah is the Source of strength. May Allah bless our Prophet Muhammad and his family and companions and grant them peace.”