Is it obligatory to wash the entire garment if urine spatters on it, or is it sufficient to wash only the affected area? And does the impurity spread throughout the entire garment if left unwashed?

If a person's trousers are splattered with urine, the spot that was hit by the urine must be washed if its location is known. However, if the location of the splattered urine is unknown, the entire trousers must be washed to purify them. This is the view of the majority of scholars.