The windscreen washer does not work. What can be the reason for this?

The windscreen washer system is essential for maintaining visibility, especially in adverse weather conditions. The functionality can be compromised for several reasons.

In this case, you identified "No water in the reservoir" and "Blocked jets" as potential issues. While these are valid reasons that could cause the windscreen washer to fail, you missed the possibility of a "Defective fuse." This is also critical because a blown fuse would cut power to the washer, preventing it from functioning at all.

According to German traffic regulations, drivers must ensure their vehicles are safe and roadworthy, which includes ensuring the windscreen washer system is fully operational. Not addressing all potential issues could lead to reduced visibility and increase the risk of accidents, which is why it's important to consider all options when diagnosing vehicle problems.