Water is not affected by Janābah
Authentic hadithعن عبد الله بن عباس رضي الله عنهما قال: اغتسل بعض أزواج النبي صلى الله عليه وسلم في جَفْنَةٍ، فجاء النبي صلى الله عليه وسلم ليتوضأ منها أو يغتسل، فقالت: له يا رسول الله، إني كنت جُنُبًا؟ فقال رسول الله صلى الله عليه وسلم : «إن الماء لا يَجْنُبُ».
‘Abdullāh ibn ‘Abbās (may Allah be pleased with him) reported: One of the Prophet's wives bathed with water placed in a large bowl. Then, the Prophet went to use this water in making ablution or taking a ritual bath, so she said to him: "O Messenger of Allah, I was in a state of Janābah." So the Messenger of Allah (may Allah's peace and blessings be upon him) said: "Water is not affected by Janābah."
Explanation
One of the Prophet's wives took a ritual bath with water placed in a large bowl. Then, the Prophet (may Allah's peace and blessings be upon him) went to make ablution or take a ritual bath with the water left over from his wife's bathing. She told him that she was in a state of Janābah when she used that water, so he instructed her that water is not affected by that, and that it retains its characteristics of being pure in itself and purifying of what is washed with it.
Source · Narrated by Ibn Majah - Narrated by At-Termedhy - Narrated by Abu Daoud
From the Hadith Encyclopedia (hadeethenc.com).