Residual detergent after washing urine-stained clothes
22-6-2017 | IslamWeb
Question:
If I wash impure urine-stained clothes in a washing machine and some residue of the detergent remains in the machine after washing and I wash them again without detergent but the residue still appears and remains even after the second washing, are the clothes pure?
Answer:
All perfect praise be to Allah, the Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad 
is His slave and Messenger.
First of all, you should know that the scholars differed in opinion regarding little water when it comes in contact with impurity and whether it becomes impure by getting in contact with it or only by being changed by the impurity (in color, taste, or smell).
The view that we adopt at our site is the view of the majority of the scholars; that little water becomes impure when it gets in contact with an impurity,
Therefore, it is obligatory to wash the impurity off the clothes before you put them in the washing machine by pouring water over the place that has become impure, and then you put them in the washing machine.
As regards putting the clothes in the washing machine while they are impure, then this leads to rendering the water impure according to the view of the majority of the scholars.
According to this view, you have to wash these clothes again with pure water.
So if you had poured water on these clothes again in the washing machine, as it appears, then the clothes became pure by doing so.
However, it is necessary to remove the impure detergent that had become impure by the first water so that the clothes can be ruled to be pure.
Of course, all this is according to the first view. As regards the second view of scholars, which is that the water does not become impure except if it becomes changed by the impurity, then you are not obliged to do so. The water that has not changed by impurity is pure and purifies these clothes. The detergent is also pure as long as it has not been changed by impurity.
We advise you to act according to this second view because it seems that you are affected with Waswasah (obsessive doubts), and a person who is affected with Waswasah should act according to the easiest view as a way of warding off hardship and avoiding inconvenience.
Allah knows best.