Do you have to change when you get to work? Do you have to wash before or after work? If this is an employer's claim or a need due to the nature of the work, it is part of working time!
Why is it important? If changing work clothes is necessary for the performance of work, the employer must consider it as working time If washing is unavoidable due to work (e.g. in health care or manufacturing), the time spent on it must also be working time
The employer cannot exclude this time from working hours by working organisation rules! If you have been unpaid for that time, you have the right to recover it.